The two biggest for-sale engines have their implementations as well as what others have posted. Unity ECS (has a pretty good general introduction to ECS) https

The two biggest for-sale engines have their implementations as well as what others have posted. Unity ECS (has a pretty good general introduction to ECS) https://docs.unity3d.com/Packages/com.unity.entities@1.3/manual/concepts-ecs.html https://docs.unity3d.com/Packages/com.unity.entities@1.3/man... Unreal https://dev.epicgames.com/documentation/en-us/unreal-engine/overview-of-mass-entity-in-unreal-engine https://dev.epicgames.com/documentation/en-us/unreal-engine/...