Amboyna burl is *THE MOST EXPENSIVE* wood on the planet. Padauk tree (Pterocarpus spp.) , nara, etc. Many of the above listing sites will have WET wood so you must be very careful when dealing with that aspect. Buying wet wood is fine if you are planing on kiln or air drying it, I would never use chemicals to dry rare exotic wood. Make no mistake about it, this is a rare growth found on a rare tree in very remote parts of the world and elephants is used to haul them out of the forest. The burl itself is often very small 20-30 kg and many places will use the root and list it as burl, as often seen with walnut burl.
Some similar type woods. stabilized spalted and dyed Birch burl, Afzelia burl, Teak burl, Asian Beach burl, Plum burl among others. Also redwood burl is somewhat similar but quite different. Of all of these Afzelia burl is much easier to get, it's quite ecologically stable and not endangered.
The other thing you should watch out for is the home stabilizing setups. If you are going to buy exotic rare wood then make sure it is professionally stabilized as the home remedy's is not sufficient nor up to par, many/most will use chemicals that will adversely affect either durability and finish; and some of the 'stabilized' chemicals are not even stabilizers at all. Better yet just buy the raw wood and stabilize it yourself.
OH the last area I was going to mention was TWO TONE. Many burls will have sapwood inclusions in random layouts, are you looking for heartwood only or two tones?
