A ton of them, there's a lot of Pokemon that are either forgettable, redundant, or otherwise uninteresting:
-All but one of the Pidgey, Spearow, Taillow, and Unfezant lines
-All but one of the Rattata, Sentret, and Zigzagoon lines
-Caterpie, Weedle, and Scatterbug lines
-Plusle and Minun
-The monkey trio
Also, Emolga and Alomomola should've been evolutions of Pachirisu and Luvdisc instead of separate Pokemon.
Irredeemable joke Pokémon, such as Luvdisc, Spinda, Stunfisk, and the Pikachu expies. Audino and the Chansey line can go bye-bye, the former being there just to make the game easier and the latter being an annoying wall. Unnecesary crutch characters (looking at you, Wurmple line) are not needed.
Reading my earlier reply, my thoughts still stand on the previous four that I mentioned, but there are a few more Pokemon I want to add to the list- the elemental monkeys. I can't believe I forgot to mention them because they are really terrible and everything about them makes me cringe. They can begone away from the games and I wouldn't lose a wink of sleep.
Scyther - no. Ugly. Scizor is cooler. Can't even use fly!!!
Tentacool family - honestly, we have so many freaking water pokemon but this is the one that appears the most. GF just get us a new annoying water Pokemon to encounter every two seconds when surfing if yu need to have a Pokemon to do that. I'm sick of Tentacool and Tentacruel
Smoochum - I've never been a fan of Jynx, but Smoochum just needs to go away. It's a little kid with way too much lipstick.
The Regis. I've never been fond of these legends. They always kind of creeped me out. Never liked them. Mostly Regigigas. If they want to keep some then the others are okay, just get rid of the big guy.