Sakura Cardcaptors: The manga only had 27 cards it was the anime that added 60+.
Digimon: They tried to copy Pokémon and it got ruined.
Hamtaro: I don't know what happened to that.
And from my POV, I'm with you, 800-1000 Pokémon are a good way to finish it before it happens, maybe it will end because Satoshi Tajiri is already old so...