Create a all loaded objects of type iterator/function about openloco

[AaronVanGeffen]

This is pattern that shows up a lot, so it's a neat idea indeed. Agreed the version that passes the ID would be better, for the same reason you've stated.

[ZehMatt]

I would vote for the forEach visitor pattern, we can also return the object id with iterators, just return std::pair instead of the object only, then you can do for(auto&& [id, object] : getLoadedObjects<T>()), there is the downside that when we don't need the id we can't mark it as maybe_unused.