Lampent

Lampent struggles to find much use, but it has a specific niche. Lampent can set and utilize Trick Room with an offensive set better than the majority of other Trick Room setters. It has a good offensive typing and coverage, alongside several useful resistances that let it set up Trick Room despite its relatively poor bulk. It also has access to two good abilities in Flash Fire and Flame Body. Flash Fire powers up its own Fire-type moves whenever Lampent is hit by one, and Flame Body can be useful for getting a surprise burn on an opponent. However, Lampent's typing also gives it some common weaknesses, including weaknesses to Rock-, Dark-, and Water-type attacks, which opens it up to a lot of damage from several moves, notably Stealth Rock, Pursuit, and Sucker Punch. Charizard gives Lampent a lot of competition as an offensive Fire-type, and Misdreavus similarly gives it competition as a Ghost-type. Trick Room in general isn't a very good strategy, but it is the main thing that makes Lampent worth using.