- Power Rangers. They've gone on long enough with far too many different seasons.
- Pokémon. Before someone attacks me with something sharp for saying it, I like Pokémon.. But the vast majority of them are all exactly the same. They could do with a different direction other than the standard collect 'em all, beat the gym leaders, beat the evil team (Rocket, Magma, Aqua whichever is featured in the particular game).
- Twilight Saga. Even the majority of people I know who've dedicated time to reading the books and who love them confess the film saga is just utterly, terribly done.
- Shrek and Toy Story. This could go for any Disney film series. Endless unrequired sequels.