Qwilfish, Dunsparce, Remoraid, just about every baby pokemon, Poliwrath (This may sound stupid to some but I just completely forgot about him until doing a pokemon quiz the other day due to Politoed's superiority), Hoppip/Skiploom/Jumpluff, Luvdisc, Relicanth, Chimecho, Mantyke, Basculin, Maractus, Alomomola, Joltik/Whateveritsevolutioniscalled, Cryogonal.
There's probably more that I've even managed to forget on a list of forgettable pokemon.
I suspect a lot of Gen V ones will be added to that in three years time because I only remember most of those from recently playing the games, they're not the best designs in the world.