I'd have to say ENxPs and INxJs, as much as I like them.
ENxPs tend to be crazy in the normal sense, just doing all kinds of random things, acting bouncy and off-the-wall, etc.
INxJs... well, they tend to sit around plotting for a long time, maybe brooding over something. And then one day, they just set into motion this brilliant yet crazy plan that is often directed at the wrong thing for the wrong reason, because of something that happened a long time ago.
Basically, ENxP insanity is just acting outlandish and novel all the time. INxJ insanity is cunning, brooding, and calculating behavior. But make no mistake, both of us are capable of being the most insane types when unhealthy.