diff --git a/crates/bevy_ecs/src/entity/index_map.rs b/crates/bevy_ecs/src/entity/index_map.rs
new file mode 100644
index 0000000000..80abf72e7f
--- /dev/null
+++ b/crates/bevy_ecs/src/entity/index_map.rs
@@ -0,0 +1,541 @@
+use core::{
+    fmt::{self, Debug, Formatter},
+    hash::BuildHasher,
+    iter::FusedIterator,
+    marker::PhantomData,
+    ops::{Deref, DerefMut, Index, IndexMut, RangeBounds},
+};
+
+#[cfg(feature = "bevy_reflect")]
+use bevy_reflect::Reflect;
+use indexmap::map::{self, IndexMap};
+
+use super::{Entity, EntityHash, EntitySetIterator, TrustedEntityBorrow};
+
+/// A [`IndexMap`] pre-configured to use [`EntityHash`] hashing.
+#[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
+#[derive(Debug, Clone)]
+pub struct EntityIndexMap<V>(pub(crate) IndexMap<Entity, V, EntityHash>);
+
+impl<V> EntityIndexMap<V> {
+    /// Creates an empty `EntityIndexMap`.
+    ///
+    /// Equivalent to [`IndexMap::with_hasher(EntityHash)`].
+    ///
+    /// [`IndexMap::with_hasher(EntityHash)`]: IndexMap::with_hasher
+    pub fn new() -> Self {
+        Self(IndexMap::with_hasher(EntityHash))
+    }
+
+    /// Creates an empty `EntityIndexMap` with the specified capacity.
+    ///
+    /// Equivalent to [`IndexMap::with_capacity_and_hasher(n, EntityHash)`].
+    ///
+    /// [`IndexMap:with_capacity_and_hasher(n, EntityHash)`]: IndexMap::with_capacity_and_hasher
+    pub fn with_capacity(n: usize) -> Self {
+        Self(IndexMap::with_capacity_and_hasher(n, EntityHash))
+    }
+
+    /// Returns the inner [`IndexMap`].
+    pub fn into_inner(self) -> IndexMap<Entity, V, EntityHash> {
+        self.0
+    }
+
+    /// Return an iterator over the key-value pairs of the map, in their order.
+    ///
+    /// Equivalent to [`IndexMap::iter`].
+    pub fn iter(&self) -> Iter<'_, V> {
+        Iter(self.0.iter(), PhantomData)
+    }
+
+    /// Return a mutable iterator over the key-value pairs of the map, in their order.
+    ///
+    /// Equivalent to [`IndexMap::iter_mut`].
+    pub fn iter_mut(&mut self) -> IterMut<'_, V> {
+        IterMut(self.0.iter_mut(), PhantomData)
+    }
+
+    /// Clears the `IndexMap` in the given index range, returning those
+    /// key-value pairs as a drain iterator.
+    ///
+    /// Equivalent to [`IndexMap::drain`].
+    pub fn drain<R: RangeBounds<usize>>(&mut self, range: R) -> Drain<'_, V> {
+        Drain(self.0.drain(range), PhantomData)
+    }
+
+    /// Return an iterator over the keys of the map, in their order.
+    ///
+    /// Equivalent to [`IndexMap::keys`].
+    pub fn keys(&self) -> Keys<'_, V> {
+        Keys(self.0.keys(), PhantomData)
+    }
+
+    /// Return an owning iterator over the keys of the map, in their order.
+    ///
+    /// Equivalent to [`IndexMap::into_keys`].
+    pub fn into_keys(self) -> IntoKeys<V> {
+        IntoKeys(self.0.into_keys(), PhantomData)
+    }
+}
+
+impl<V> Default for EntityIndexMap<V> {
+    fn default() -> Self {
+        Self(Default::default())
+    }
+}
+
+impl<V> Deref for EntityIndexMap<V> {
+    type Target = IndexMap<Entity, V, EntityHash>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<V> DerefMut for EntityIndexMap<V> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<'a, V: Copy> Extend<(&'a Entity, &'a V)> for EntityIndexMap<V> {
+    fn extend<T: IntoIterator<Item = (&'a Entity, &'a V)>>(&mut self, iter: T) {
+        self.0.extend(iter);
+    }
+}
+
+impl<V> Extend<(Entity, V)> for EntityIndexMap<V> {
+    fn extend<T: IntoIterator<Item = (Entity, V)>>(&mut self, iter: T) {
+        self.0.extend(iter);
+    }
+}
+
+impl<V, const N: usize> From<[(Entity, V); N]> for EntityIndexMap<V> {
+    fn from(value: [(Entity, V); N]) -> Self {
+        Self(IndexMap::from_iter(value))
+    }
+}
+
+impl<V> FromIterator<(Entity, V)> for EntityIndexMap<V> {
+    fn from_iter<I: IntoIterator<Item = (Entity, V)>>(iterable: I) -> Self {
+        Self(IndexMap::from_iter(iterable))
+    }
+}
+
+impl<V, Q: TrustedEntityBorrow + ?Sized> Index<&Q> for EntityIndexMap<V> {
+    type Output = V;
+    fn index(&self, key: &Q) -> &V {
+        self.0.index(&key.entity())
+    }
+}
+
+impl<V> Index<usize> for EntityIndexMap<V> {
+    type Output = V;
+    fn index(&self, key: usize) -> &V {
+        self.0.index(key)
+    }
+}
+
+impl<V, Q: TrustedEntityBorrow + ?Sized> IndexMut<&Q> for EntityIndexMap<V> {
+    fn index_mut(&mut self, key: &Q) -> &mut V {
+        self.0.index_mut(&key.entity())
+    }
+}
+
+impl<V> IndexMut<usize> for EntityIndexMap<V> {
+    fn index_mut(&mut self, key: usize) -> &mut V {
+        self.0.index_mut(key)
+    }
+}
+
+impl<'a, V> IntoIterator for &'a EntityIndexMap<V> {
+    type Item = (&'a Entity, &'a V);
+    type IntoIter = Iter<'a, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        Iter(self.0.iter(), PhantomData)
+    }
+}
+
+impl<'a, V> IntoIterator for &'a mut EntityIndexMap<V> {
+    type Item = (&'a Entity, &'a mut V);
+    type IntoIter = IterMut<'a, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        IterMut(self.0.iter_mut(), PhantomData)
+    }
+}
+
+impl<V> IntoIterator for EntityIndexMap<V> {
+    type Item = (Entity, V);
+    type IntoIter = IntoIter<V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIter(self.0.into_iter(), PhantomData)
+    }
+}
+
+impl<V1, V2, S2> PartialEq<IndexMap<Entity, V2, S2>> for EntityIndexMap<V1>
+where
+    V1: PartialEq<V2>,
+    S2: BuildHasher,
+{
+    fn eq(&self, other: &IndexMap<Entity, V2, S2>) -> bool {
+        self.0.eq(other)
+    }
+}
+
+impl<V1, V2> PartialEq<EntityIndexMap<V2>> for EntityIndexMap<V1>
+where
+    V1: PartialEq<V2>,
+{
+    fn eq(&self, other: &EntityIndexMap<V2>) -> bool {
+        self.0.eq(other)
+    }
+}
+
+impl<V: Eq> Eq for EntityIndexMap<V> {}
+
+/// An iterator over the entries of an [`EntityIndexMap`].
+///
+/// This `struct` is created by the [`EntityIndexMap::iter`] method.
+/// See its documentation for more.
+pub struct Iter<'a, V, S = EntityHash>(map::Iter<'a, Entity, V>, PhantomData<S>);
+
+impl<'a, V> Iter<'a, V> {
+    /// Returns the inner [`Iter`](map::Iter).
+    pub fn into_inner(self) -> map::Iter<'a, Entity, V> {
+        self.0
+    }
+}
+
+impl<'a, V> Deref for Iter<'a, V> {
+    type Target = map::Iter<'a, Entity, V>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a, V> Iterator for Iter<'a, V> {
+    type Item = (&'a Entity, &'a V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl<V> DoubleEndedIterator for Iter<'_, V> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl<V> ExactSizeIterator for Iter<'_, V> {}
+
+impl<V> FusedIterator for Iter<'_, V> {}
+
+impl<V> Clone for Iter<'_, V> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone(), PhantomData)
+    }
+}
+
+impl<V: Debug> Debug for Iter<'_, V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("Iter").field(&self.0).field(&self.1).finish()
+    }
+}
+
+impl<V> Default for Iter<'_, V> {
+    fn default() -> Self {
+        Self(Default::default(), PhantomData)
+    }
+}
+
+/// A mutable iterator over the entries of an [`EntityIndexMap`].
+///
+/// This `struct` is created by the [`EntityIndexMap::iter_mut`] method.
+/// See its documentation for more.
+pub struct IterMut<'a, V, S = EntityHash>(map::IterMut<'a, Entity, V>, PhantomData<S>);
+
+impl<'a, V> IterMut<'a, V> {
+    /// Returns the inner [`IterMut`](map::IterMut).
+    pub fn into_inner(self) -> map::IterMut<'a, Entity, V> {
+        self.0
+    }
+}
+
+impl<'a, V> Deref for IterMut<'a, V> {
+    type Target = map::IterMut<'a, Entity, V>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a, V> Iterator for IterMut<'a, V> {
+    type Item = (&'a Entity, &'a mut V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl<V> DoubleEndedIterator for IterMut<'_, V> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl<V> ExactSizeIterator for IterMut<'_, V> {}
+
+impl<V> FusedIterator for IterMut<'_, V> {}
+
+impl<V: Debug> Debug for IterMut<'_, V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("IterMut")
+            .field(&self.0)
+            .field(&self.1)
+            .finish()
+    }
+}
+
+impl<V> Default for IterMut<'_, V> {
+    fn default() -> Self {
+        Self(Default::default(), PhantomData)
+    }
+}
+
+/// An owning iterator over the entries of an [`IndexMap`].
+///
+/// This `struct` is created by the [`IndexMap::into_iter`] method
+/// (provided by the [`IntoIterator`] trait). See its documentation for more.
+pub struct IntoIter<V, S = EntityHash>(map::IntoIter<Entity, V>, PhantomData<S>);
+
+impl<V> IntoIter<V> {
+    /// Returns the inner [`IntoIter`](map::IntoIter).
+    pub fn into_inner(self) -> map::IntoIter<Entity, V> {
+        self.0
+    }
+}
+
+impl<V> Deref for IntoIter<V> {
+    type Target = map::IntoIter<Entity, V>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<V> Iterator for IntoIter<V> {
+    type Item = (Entity, V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl<V> DoubleEndedIterator for IntoIter<V> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl<V> ExactSizeIterator for IntoIter<V> {}
+
+impl<V> FusedIterator for IntoIter<V> {}
+
+impl<V: Clone> Clone for IntoIter<V> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone(), PhantomData)
+    }
+}
+
+impl<V: Debug> Debug for IntoIter<V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("IntoIter")
+            .field(&self.0)
+            .field(&self.1)
+            .finish()
+    }
+}
+
+impl<V> Default for IntoIter<V> {
+    fn default() -> Self {
+        Self(Default::default(), PhantomData)
+    }
+}
+
+/// A draining iterator over the entries of an [`EntityIndexMap`].
+///
+/// This `struct` is created by the [`EntityIndexMap::drain`] method.
+/// See its documentation for more.
+pub struct Drain<'a, V, S = EntityHash>(map::Drain<'a, Entity, V>, PhantomData<S>);
+
+impl<'a, V> Drain<'a, V> {
+    /// Returns the inner [`Drain`](map::Drain).
+    pub fn into_inner(self) -> map::Drain<'a, Entity, V> {
+        self.0
+    }
+}
+
+impl<'a, V> Deref for Drain<'a, V> {
+    type Target = map::Drain<'a, Entity, V>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<V> Iterator for Drain<'_, V> {
+    type Item = (Entity, V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl<V> DoubleEndedIterator for Drain<'_, V> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl<V> ExactSizeIterator for Drain<'_, V> {}
+
+impl<V> FusedIterator for Drain<'_, V> {}
+
+impl<V: Debug> Debug for Drain<'_, V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("Drain")
+            .field(&self.0)
+            .field(&self.1)
+            .finish()
+    }
+}
+
+/// An iterator over the keys of an [`EntityIndexMap`].
+///
+/// This `struct` is created by the [`EntityIndexMap::keys`] method.
+/// See its documentation for more.
+pub struct Keys<'a, V, S = EntityHash>(map::Keys<'a, Entity, V>, PhantomData<S>);
+
+impl<'a, V> Keys<'a, V> {
+    /// Returns the inner [`Keys`](map::Keys).
+    pub fn into_inner(self) -> map::Keys<'a, Entity, V> {
+        self.0
+    }
+}
+
+impl<'a, V, S> Deref for Keys<'a, V, S> {
+    type Target = map::Keys<'a, Entity, V>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a, V> Iterator for Keys<'a, V> {
+    type Item = &'a Entity;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl<V> DoubleEndedIterator for Keys<'_, V> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl<V> ExactSizeIterator for Keys<'_, V> {}
+
+impl<V> FusedIterator for Keys<'_, V> {}
+
+impl<V> Index<usize> for Keys<'_, V> {
+    type Output = Entity;
+
+    fn index(&self, index: usize) -> &Entity {
+        self.0.index(index)
+    }
+}
+
+impl<V> Clone for Keys<'_, V> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone(), PhantomData)
+    }
+}
+
+impl<V: Debug> Debug for Keys<'_, V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("Keys").field(&self.0).field(&self.1).finish()
+    }
+}
+
+impl<V> Default for Keys<'_, V> {
+    fn default() -> Self {
+        Self(Default::default(), PhantomData)
+    }
+}
+
+// SAFETY: Keys stems from a correctly behaving `IndexMap<Entity, V, EntityHash>`.
+unsafe impl<V> EntitySetIterator for Keys<'_, V> {}
+
+/// An owning iterator over the keys of an [`EntityIndexMap`].
+///
+/// This `struct` is created by the [`EntityIndexMap::into_keys`] method.
+/// See its documentation for more.
+pub struct IntoKeys<V, S = EntityHash>(map::IntoKeys<Entity, V>, PhantomData<S>);
+
+impl<V> IntoKeys<V> {
+    /// Returns the inner [`IntoKeys`](map::IntoKeys).
+    pub fn into_inner(self) -> map::IntoKeys<Entity, V> {
+        self.0
+    }
+}
+
+impl<V> Deref for IntoKeys<V> {
+    type Target = map::IntoKeys<Entity, V>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<V> Iterator for IntoKeys<V> {
+    type Item = Entity;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl<V> DoubleEndedIterator for IntoKeys<V> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl<V> ExactSizeIterator for IntoKeys<V> {}
+
+impl<V> FusedIterator for IntoKeys<V> {}
+
+impl<V: Debug> Debug for IntoKeys<V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("IntoKeys")
+            .field(&self.0)
+            .field(&self.1)
+            .finish()
+    }
+}
+
+impl<V> Default for IntoKeys<V> {
+    fn default() -> Self {
+        Self(Default::default(), PhantomData)
+    }
+}
+
+// SAFETY: IntoKeys stems from a correctly behaving `IndexMap<Entity, V, EntityHash>`.
+unsafe impl<V> EntitySetIterator for IntoKeys<V> {}
diff --git a/crates/bevy_ecs/src/entity/index_set.rs b/crates/bevy_ecs/src/entity/index_set.rs
new file mode 100644
index 0000000000..60825727cf
--- /dev/null
+++ b/crates/bevy_ecs/src/entity/index_set.rs
@@ -0,0 +1,364 @@
+use core::{
+    fmt::{self, Debug, Formatter},
+    hash::BuildHasher,
+    iter::FusedIterator,
+    marker::PhantomData,
+    ops::{BitAnd, BitOr, BitXor, Deref, DerefMut, Index, RangeBounds, Sub},
+};
+
+use indexmap::set::{self, IndexSet};
+
+use super::{Entity, EntityHash, EntitySetIterator};
+
+/// An [`IndexSet`] pre-configured to use [`EntityHash`] hashing.
+#[derive(Debug, Clone, Default)]
+pub struct EntityIndexSet(pub(crate) IndexSet<Entity, EntityHash>);
+
+impl EntityIndexSet {
+    /// Creates an empty `EntityIndexSet`.
+    ///
+    /// Equivalent to [`IndexSet::with_hasher(EntityHash)`].
+    ///
+    /// [`IndexSet::with_hasher(EntityHash)`]: IndexSet::with_hasher
+    pub fn new() -> Self {
+        Self(IndexSet::with_hasher(EntityHash))
+    }
+
+    /// Creates an empty `EntityIndexSet` with the specified capacity.
+    ///
+    /// Equivalent to [`IndexSet::with_capacity_and_hasher(n, EntityHash)`].
+    ///
+    /// [`IndexSet::with_capacity_and_hasher(n, EntityHash)`]: IndexSet::with_capacity_and_hasher
+    pub fn with_capacity(n: usize) -> Self {
+        Self(IndexSet::with_capacity_and_hasher(n, EntityHash))
+    }
+
+    /// Returns the inner [`IndexSet`].
+    pub fn into_inner(self) -> IndexSet<Entity, EntityHash> {
+        self.0
+    }
+
+    /// Clears the `IndexSet` in the given index range, returning those values
+    /// as a drain iterator.
+    ///
+    /// Equivalent to [`IndexSet::drain`].
+    pub fn drain<R: RangeBounds<usize>>(&mut self, range: R) -> Drain<'_> {
+        Drain(self.0.drain(range), PhantomData)
+    }
+
+    /// Return an iterator over the values of the set, in their order.
+    ///
+    /// Equivalent to [`IndexSet::iter`].
+    pub fn iter(&self) -> Iter<'_> {
+        Iter(self.0.iter(), PhantomData)
+    }
+}
+
+impl Deref for EntityIndexSet {
+    type Target = IndexSet<Entity, EntityHash>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for EntityIndexSet {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<'a> IntoIterator for &'a EntityIndexSet {
+    type Item = &'a Entity;
+
+    type IntoIter = Iter<'a>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        Iter((&self.0).into_iter(), PhantomData)
+    }
+}
+
+impl IntoIterator for EntityIndexSet {
+    type Item = Entity;
+
+    type IntoIter = IntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIter(self.0.into_iter(), PhantomData)
+    }
+}
+
+impl BitAnd for &EntityIndexSet {
+    type Output = EntityIndexSet;
+
+    fn bitand(self, rhs: Self) -> Self::Output {
+        EntityIndexSet(self.0.bitand(&rhs.0))
+    }
+}
+
+impl BitOr for &EntityIndexSet {
+    type Output = EntityIndexSet;
+
+    fn bitor(self, rhs: Self) -> Self::Output {
+        EntityIndexSet(self.0.bitor(&rhs.0))
+    }
+}
+
+impl BitXor for &EntityIndexSet {
+    type Output = EntityIndexSet;
+
+    fn bitxor(self, rhs: Self) -> Self::Output {
+        EntityIndexSet(self.0.bitxor(&rhs.0))
+    }
+}
+
+impl Sub for &EntityIndexSet {
+    type Output = EntityIndexSet;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        EntityIndexSet(self.0.sub(&rhs.0))
+    }
+}
+
+impl<'a> Extend<&'a Entity> for EntityIndexSet {
+    fn extend<T: IntoIterator<Item = &'a Entity>>(&mut self, iter: T) {
+        self.0.extend(iter);
+    }
+}
+
+impl Extend<Entity> for EntityIndexSet {
+    fn extend<T: IntoIterator<Item = Entity>>(&mut self, iter: T) {
+        self.0.extend(iter);
+    }
+}
+
+impl<const N: usize> From<[Entity; N]> for EntityIndexSet {
+    fn from(value: [Entity; N]) -> Self {
+        Self(IndexSet::from_iter(value))
+    }
+}
+
+impl FromIterator<Entity> for EntityIndexSet {
+    fn from_iter<I: IntoIterator<Item = Entity>>(iterable: I) -> Self {
+        Self(IndexSet::from_iter(iterable))
+    }
+}
+
+impl<S2> PartialEq<IndexSet<Entity, S2>> for EntityIndexSet
+where
+    S2: BuildHasher,
+{
+    fn eq(&self, other: &IndexSet<Entity, S2>) -> bool {
+        self.0.eq(other)
+    }
+}
+
+impl PartialEq for EntityIndexSet {
+    fn eq(&self, other: &EntityIndexSet) -> bool {
+        self.0.eq(other)
+    }
+}
+
+impl Eq for EntityIndexSet {}
+
+impl Index<usize> for EntityIndexSet {
+    type Output = Entity;
+    fn index(&self, key: usize) -> &Entity {
+        self.0.index(key)
+    }
+}
+
+/// An iterator over the items of an [`EntityIndexSet`].
+///
+/// This struct is created by the [`iter`] method on [`EntityIndexSet`]. See its documentation for more.
+///
+/// [`iter`]: EntityIndexSet::iter
+pub struct Iter<'a, S = EntityHash>(set::Iter<'a, Entity>, PhantomData<S>);
+
+impl<'a> Iter<'a> {
+    /// Returns the inner [`Iter`](set::Iter).
+    pub fn into_inner(self) -> set::Iter<'a, Entity> {
+        self.0
+    }
+}
+
+impl<'a> Deref for Iter<'a> {
+    type Target = set::Iter<'a, Entity>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a> Iterator for Iter<'a> {
+    type Item = &'a Entity;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl DoubleEndedIterator for Iter<'_> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl ExactSizeIterator for Iter<'_> {}
+
+impl FusedIterator for Iter<'_> {}
+
+impl Clone for Iter<'_> {
+    fn clone(&self) -> Self {
+        Self(self.0.clone(), PhantomData)
+    }
+}
+
+impl Debug for Iter<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("Iter").field(&self.0).field(&self.1).finish()
+    }
+}
+
+impl Default for Iter<'_> {
+    fn default() -> Self {
+        Self(Default::default(), PhantomData)
+    }
+}
+
+// SAFETY: Iter stems from a correctly behaving `IndexSet<Entity, EntityHash>`.
+unsafe impl EntitySetIterator for Iter<'_> {}
+
+/// Owning iterator over the items of an [`EntityIndexSet`].
+///
+/// This struct is created by the [`into_iter`] method on [`EntityIndexSet`] (provided by the [`IntoIterator`] trait). See its documentation for more.
+///
+/// [`into_iter`]: EntityIndexSet::into_iter
+pub struct IntoIter<S = EntityHash>(set::IntoIter<Entity>, PhantomData<S>);
+
+impl IntoIter {
+    /// Returns the inner [`IntoIter`](set::IntoIter).
+    pub fn into_inner(self) -> set::IntoIter<Entity> {
+        self.0
+    }
+}
+
+impl Deref for IntoIter {
+    type Target = set::IntoIter<Entity>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Iterator for IntoIter {
+    type Item = Entity;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl DoubleEndedIterator for IntoIter {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl ExactSizeIterator for IntoIter {}
+
+impl FusedIterator for IntoIter {}
+
+impl Clone for IntoIter {
+    fn clone(&self) -> Self {
+        Self(self.0.clone(), PhantomData)
+    }
+}
+
+impl Debug for IntoIter {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("IntoIter")
+            .field(&self.0)
+            .field(&self.1)
+            .finish()
+    }
+}
+
+impl Default for IntoIter {
+    fn default() -> Self {
+        Self(Default::default(), PhantomData)
+    }
+}
+
+// SAFETY: IntoIter stems from a correctly behaving `IndexSet<Entity, EntityHash>`.
+unsafe impl EntitySetIterator for IntoIter {}
+
+/// A draining iterator over the items of an [`EntityIndexSet`].
+///
+/// This struct is created by the [`drain`] method on [`EntityIndexSet`]. See its documentation for more.
+///
+/// [`drain`]: EntityIndexSet::drain
+pub struct Drain<'a, S = EntityHash>(set::Drain<'a, Entity>, PhantomData<S>);
+
+impl<'a> Drain<'a> {
+    /// Returns the inner [`Drain`](set::Drain).
+    pub fn into_inner(self) -> set::Drain<'a, Entity> {
+        self.0
+    }
+}
+
+impl<'a> Deref for Drain<'a> {
+    type Target = set::Drain<'a, Entity>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a> Iterator for Drain<'a> {
+    type Item = Entity;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl DoubleEndedIterator for Drain<'_> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl ExactSizeIterator for Drain<'_> {}
+
+impl FusedIterator for Drain<'_> {}
+
+impl Debug for Drain<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("Drain")
+            .field(&self.0)
+            .field(&self.1)
+            .finish()
+    }
+}
+
+// SAFETY: Drain stems from a correctly behaving `IndexSet<Entity, EntityHash>`.
+unsafe impl EntitySetIterator for Drain<'_> {}
+
+// SAFETY: Difference stems from two correctly behaving `IndexSet<Entity, EntityHash>`s.
+unsafe impl EntitySetIterator for set::Difference<'_, Entity, EntityHash> {}
+
+// SAFETY: Intersection stems from two correctly behaving `IndexSet<Entity, EntityHash>`s.
+unsafe impl EntitySetIterator for set::Intersection<'_, Entity, EntityHash> {}
+
+// SAFETY: SymmetricDifference stems from two correctly behaving `IndexSet<Entity, EntityHash>`s.
+unsafe impl EntitySetIterator for set::SymmetricDifference<'_, Entity, EntityHash, EntityHash> {}
+
+// SAFETY: Union stems from two correctly behaving `IndexSet<Entity, EntityHash>`s.
+unsafe impl EntitySetIterator for set::Union<'_, Entity, EntityHash> {}
+
+// SAFETY: Splice stems from a correctly behaving `IndexSet<Entity, EntityHash>`s.
+unsafe impl<I: Iterator<Item = Entity>> EntitySetIterator
+    for set::Splice<'_, I, Entity, EntityHash>
+{
+}
diff --git a/crates/bevy_ecs/src/entity/mod.rs b/crates/bevy_ecs/src/entity/mod.rs
index 4666ac2c9d..3fa63d37fa 100644
--- a/crates/bevy_ecs/src/entity/mod.rs
+++ b/crates/bevy_ecs/src/entity/mod.rs
@@ -56,6 +56,12 @@ pub use hash::*;
 pub mod hash_map;
 pub mod hash_set;
 
+mod index_map;
+mod index_set;
+
+pub use index_map::EntityIndexMap;
+pub use index_set::EntityIndexSet;
+
 use crate::{
     archetype::{ArchetypeId, ArchetypeRow},
     identifier::{