The tiny-ecs library is quite popular here, likely because it’s very easy to use and allows for flexible implementation. The @dlannan made an interesting topic about it: Flix Procedural Training and Movie Making.
There is a lot of discussion on the web about ECS, saying that additional tools are more crucial for this approach if compared to others.
An ECS admin panel can be a powerful tool. Since this type of architecture allows you to inspect and modify entities and systems easily at runtime, having a set of instruments to operate with it would be very cool!