Looking at the learnset for Incinerate, by levelup it's fairly standard (everything that learns it naturally is a Fire-type, or evolves into one). By TM there's a few less conventional picks, though they're mainly you might expect: Nidos, Clefable, Slowbro, Dragonite, Dunsparce, Kecleon, Salamence, Gourgeist, Goodra. Most are those which learn Fire attacks with by TM or tutoring.
There are still a few odd ones, though: Machamp, Marowak, Sableye, Mawile, Scrafty, Tornadus, Thundurus. Part of me wonders if Incinerate's initially garbage base power made Game Freak quite liberal with who could learn it.