Blastoise
I think Blastoise could make a splash in the meta. Have Shell Smash and a good physical move pool along with enough special move to get by. With it special move pool it hit every with normal effectiveness besides Primarina, Toxapex, Golisopod, Araquanid, and Jellicent. And physical it has the movepool to hit every for normal effectiveness.
Cobalion, Terrakion, and Virzion
I'm grouping all of these guys together because they mostly play the same. All can run Choice Band and Swords Dance. They probably could run their primary type stab, close combat or sacred sword, then megahorn or a different coverage move and the last move could be rocks or move coverage.
Kyurem Base
I don't see regular kyurem making a impact in the scene. It maybe could be support but overwise nothing I can think of.
Kyurem Black
I think Black could run the same the same as last gen as a mixed sweeper. Also it could run a DD set.
Kyurem White
Right now White is in Ubers but I think it could be OU. White puts the grass, steels, and water of the meta in check. But it can be stopped by Special Dragapult, Physical Life Orb Dragapult, Assault Vest Melmetal, all of the musketeers that have Band close combat or one SD close combat, Band Zeraora, etc. So I think Kyurem could come down.
Mew
Mew can learn every TM and TR and is the only other Pokemon that can learn transform. It can run a imprision and transform set to make any Pokemon struggle. It all so can be ran as a scarfer to help patch up holes to hit threats you can't handle otherwise.
Keldeo
I can see Keldeo being ran as a Scarf/Specs user. With air slash to kill grasses, hydro pump and aura sphere/secret sword for stabs, and icy wind, taunt, toxic, reflect, or roar for support.
Others
I think that Celebi, Venusaur, Jirachi(maybe), Decidueye, Necrozma-Base, Incineroar, and Primarina will be in the lower tiers. Most I think will end up in UU or UUBL.