Australia has an incredible amount of very cool wood. Hit up Peter and Kim at thetimberjoint.com for ringed gidgee (which is like if desert ironwood and curly koa had a baby: super cool curl on a very hard and dense wood), sheoak, buloke, and budgeroo burl. They almost always have ringed gidgee in stock but the other species come and go.
Tasmanian blackwood is in the same family as koa, and it can also become crazy curly with high chatoyance. It seems rare to find pieces with the irregular curl or with deep compression curl like koa sometimes shows tho, but you can often find very tight fiddleback curl figure in taz blackwood easier than koa.
There's a ton of different Aussie burls that are beautiful too. Mallee, morrel, jarrah, coolibah, yorrel, box, and a bunch of others I can't remember off the top of my head. If you google Australian burls or Aussie burls, you can also dig up some sources to buy them from.
The interesting thing about Australian wood is that a lot of the cool stuff is supposedly grown sustainably versus a lot of other woods around the world that are just being decimated.