Diancie

Diancie's typing is unique and backed up by incredible defenses, allowing it to take hits from prominent threats in the tier such as Mega Absol, Hydreigon, and Entei. It also has decent offensive stats and coverage that allow it to not be complete setup bait to most Pokemon, as well as a lot of tools to use to work as an effective Trick Room setter. Diancie's STAB Diamond Storm and access to Stealth Rock give it offensive pressure against common Defoggers. On the downside, some Pokemon still take advantage of it, like Suicune and Feraligatr. Diancie also has low Speed and no priority, allowing it to get picked off quite easily by the likes of Roserade, Mega Sceptile, and Mega Blastoise. Its typing, while unique and useful, leaves it with many weaknesses to Pokemon like Nidoqueen and Roserade, as well as a glaring 4x weakness to Steel-type attacks.