Mew

Mew distinguishes itself from other common Psychic-types like Slowbro and Cresselia by virtue of its incredibly deep movepool, which, when combined with its rounded statline, lets it run a variety of viable sets. Mew can take advantage of common utility and defensive Pokemon like Cyclizar and Gastrodon, making progress against them with its many utility moves or using them as setup fodder while preparing for a sweep. Mew's access to Draining Kiss also makes Nasty Plot sets deceptively hard to take down, letting it consistently punch holes through teams. However, Mew's "Master of None" statline and lackluster typing, the latter of which gives it weaknesses to common attacks like Knock Off and U-turn, mean that it can find itself outdone by more specialized Pokemon. Due to its lack of recovery outside of Draining Kiss, Gastrodon and Chesnaught give it stiff competition as a Spikes setter, while other special sweepers like Gengar and Raikou have better offensive typings and stats. RU also has no shortage of Psychic-types that compete with Mew for a teamslot. Slowbro and Reuniclus have better bulk and reliable recovery, Armarouge is better at punching holes through teams with its powerful Fire-type STAB moves, and Jirachi has an identical statline to Mew while also having a better defensive typing and ability. While Mew's Speed tier is fairly solid, it's prone to being revenge killed by dangerous Pokemon like Gengar, Mienshao, and Noivern.