VGMdb has the best Franchise system, I think.
You should be able to link a Franchise to any kinds of entities.
I don’t know if we should call it Franchise, though. It sounds quite like McDonald’s and highly commercial crap stuff like that.
Maybe it should be called Topic or Theme or Category… or Franchise if it’s what people are used to (I’m not really used to this, but I’m not using English in daily life).
Don’t know.
By the way, maybe let’s just use tags, they are already available.
As suggested by a comment in the above ticket, linking to https://tickets.metabrainz.org/browse/MBS-8277.
Franchise Tag example from another topic: Tag “star wars” - MusicBrainz 