EnTT
A fast and reliable entity component system (ECS) and much more
...Over time the codebase has grown as more and more classes and functionalities were added. Statically generated integer identifiers for types (assigned either at compile-time or at runtime). A constexpr utility for human readable resource names. An incredibly fast entity-component system based on sparse sets, with its own pay for what you use policy to adjust performance and memory usage according to the users' requirements. Offers a minimal configuration system built using the monostate pattern.