Hey! Final Fantasy was actually near the top in my earlier drafts! I unfortunately had to cut it because I wanted to focus on franchises that either tell one continuous story, or have a canon timeline - Pokemon, for example, frequently mentions past events, has cross over characters and builds on what came before (I did also count each game from each generation, so Red, Blue and Yellow are all their own entries). Final Fantasy definitely does reference itself, but as you said, it's more fan theory territory when connecting them canonically.
You make some good points though, and I definitely considered these when writing the list!
