Xatu

Although this strange mystical bird seems outclassed, she has a few perks over fellow Psychic-types like Alakazam and Uxie. High Speed and Special Attack, along with a decent offensive movepool, turn Xatu into a respectable sweeper. Her typing gives her a 4x resistance to Fighting-type attacks, making her a decent supporter as well. Xatu's movepool includes great supporting options, such as Wish, Roost, Haze, and Light Screen; she even has access to Baton Pass to escape Pursuit users and/or pass Calm Mind and Substitute. While Xatu seems like an impeccable Pokemon, her weakness to Stealth Rock and Pursuit make it harder to switch her in, and she requires good prediction against Dark- and Ghost-types. All in all, Xatu will make a great addition to your team, just make sure she uses a set that isn't outclassed by anything else in UU.