I try to understand (hybrid) ECS and are looking for some best practices. I have some base components, which are used very often, but I am thinking about derived components as well
You may create Selected, Unselected, Focused, Unfocused, Player and Enemy components. This way you will be able to sort out and filter the entities by these components easily. If you wanna filter out those entities that have either Focused or Unfocused component, you can also add Focus component just to group those