Fairy Queen
Lover of the Fairy type
So which of the Generation 7 pokemon will be the most popular in competitive battling?
Toxapex and Celesteela have both come forth as prominent pokemon this Gen, both for their ability to stall and take attacks like there is no tomorrow. Both will be OU, and not in the low tier. Specific counters to them will likely see places on team, for nothing than to counter them. Toxapex is not only incredibly bulky, but it has reliable recovery in the form of recover and regenerator, and is the best toxic spreader, period (with the exception of Salazzle). It can also be quite offensive, with a venoshock merciless combination. It also isn't completely walled by Steel types, because it can spread burns with Scald as well. It's typing is also very good. Celesteela is yet another bulky pokemon, with 97/103/101 and arguably the best defensive typing in the game. It is immune to poison (bar Salazzle) and burn has been nerfed. While it is set back by its lack of recovery, it does have access to the random leech seed, and has some great moves (Heavy Slam which almost always does max damage, Flamethrower, Giga Drain, Autotomize, Earthquake, etc). Very hard pokemon to take down without the right tools.
Pheromosa and Kartana will also see some great usage. Pheromosa is an alt Deoxys, but has several factors over it. It has a base 151 speed, which means it outspeeds almost all pokemon, especially the common speedsters, like Mega Alakazam, Mega Aerodactyl, Mega Beedrill, Deoxys, etc. Its base 137 attack stats means that it hits VERY hard, and access to powerful moves such as U-turn and High Jump kick mean it will dent anything that isn't immune or doubly resistant. It also has Rapid Spin and Quiver Dance, for what it is worth. It is, however, set back by its HORRIBLE defenses, but it is nonetheless a POWERFUL glasscannon. Kartana has one of the highest attack stats in the game and also has a respectable 109 base speed, which means it outspeeds a lot of pokemon. Beast Boost also works in its favor, by acting like Moxie, making it hit even more powerfully. Its typing is also really good, and it has high defense. It is, however, set back by its terrible special defense and HP.
Other popular pokemon include the Tapus and Minior.