Multi dyed crazy color burls and hybrids, try theblankspace.us, akdesigns.net, @derangeddonkey on Instagram, @exotic_blanks on Instagram, @5tharrowknives on Instagram.
I'll ditto Randy on Craig Stevens and Exotic Burl Woods/Matt Manning through eBay. I've bought multiple items from both and they live up to the pics if not better sometimes. Isle Woods on eBay has really great stuff as well, and I just bought a bunch of amboyna from him.
Mark at Burlsource.us gets some super high quality stuff but it sells very quickly. Ben at Greenbergwoods.com gets a lot of really cool exotic burls too.
Edited to add: I'm always trolling eBay and Etsy because you never know who's selling their excess or who is making some cool stabilized wood. There's a number of Russian, Ukranian, and other eastern european folks selling nice looking dyed and stabilized woods. But you have to be somewhat careful, one block I got from one of them looked nice but it was obvious that it didn't take up much of the stabilizing resin because it was much lighter than I would've expected for that particular burl after stabilization (meaning their process didn't put as much resin into the wood as some others).