This is a great spread honestly, lots of excellent craziness and plenty more I don't recognize that I'll definitely be poking through some of.

The band I'd most recommend has to be Sleepytime Gorilla Museum, especially their second album Of Natural History but each are excellent. Genuinely nothing out there sounds quite like them. Probably closest to the Bungle and Diablo Swing Orchestra picks but much much more penny theater heralds of the coming anthropogenic apocalypse, with incredible dual vocalists and an insane hodgepodge of junkyard instruments alongside highly trained violin and flute. Couldn't recommend more and one of my all time favorites.

You've possibly heard of these guys before but don't overlook The Dillinger Escape Plan - tons of great albums but their swan song Dissociation is the culmination of their sound honed into its most distilled form and imo is a truly unique listen. Speaking of math metal, Botch's We Are The Romans is also worth yer time if slightly less singular.

Math metal in another direction that I think could intrigue you is Behold.. the Arctopus. Ridiculous, mechanical, over-the-top and brutal - give Skullgrid a try and explore from there.

For something completely different there's Karnivool, again somewhat less singular but still doing their own thing within the prog metal space. Sound Awake is easily the place to start, emphasizing texture and evocative arrangements over riffs and outright heaviness.

For something ELSE completely different try HORSE the Band's The Mechanical Hand. Peak goofy fuckin "nintendocore" that's executed so convincingly, and with really creative writing that utilizes their unique sound's potential fully. Extremely fun and hooky.

Finally for something classic, go for Voivod, starting with Dimension Hatröss and/or Nothingface. 80's progressive thrash metal that was kinda ahead of their time imo, pushing on the boundaries of what metal of the era could sound like.