Litten

Litten may have a good ability, but everything else about it is underwhelming in the competitive scene. Its movepool is quite shallow despite its access to useful moves like U-turn, its typing is unimpressive, its stats are average at best, and it's horribly outclassed by other Fire-types such as Ponyta and Larvesta due to their better stats and access to reliable recovery; furthermore, despite being a Fire-type, Litten cannot check Pawniard due to Intimidate activating Defiant. Its lack of coverage and utility options means you're better off using a different Pokemon most of the time.