Pokémon
(Don’t know how this isn’t a species tag yet.)
I would say that it’s because it’s used for the entire franchise, not for Pokémon as a group of creatures – images relating to other aspects of the franchise, such as pokéballs and Pokémon trainers (
1,
2 ), ponified human characters (
1,
2 ), humanized characters and OCs (
1,
2 ), canon characters wearing outfits from the series (
1,
2 ) and straight crossovers (
1,
2 ) all get the tag even with none of the actual creatures involved.