Frankly, they're very few of them. It seems like GF has ran out of idea on how to make niche spots on Pokemon and they're afraid of making strong Pokemon that outclasses old fan favorite (like Gen V powerhouses).

Here's my conservative estimate of the new species that's gonna be OU. This shows that regardless of what fairyfags believe, Dragons will still be the dominant force in the metagame, closely followed by Ghost and Water due to Steel nerf.

There's a couple of Ghosts pokemon in Gen 6 like Klefki, Trevenant and Gourgeist that might be OU for spinblocking, but it all really depends on whether Mega-Gengar got banned or not (and hence the pool of spinners) so I didn't include them in the pic.