It's all nice. Elk is my least favorite due to porosity but is still more durable than ivory in terms of cracking. My favorite for density is moose and mule deer. For visual character I prefer caribou & mule deer. I use whitetail deer, blacktail deer, mule deer, caribou, moose, & elk. I have used european stag & it's very solid & dense, as well as very white. Alaskan moose is the densest but the only stuff that's good in it is a few inches in the base & the very tips of the tines. All are pretty much white with the exception of mule deer, which is charcoal grey, caribou that has greens & pinks & purple swirls, and elk that is often two tone with white & grey, usually speckled due to pores.
Other notable horns/teeth are water buffalo horn, which is black with sometimes grey & white lines, and hippo teeth that is very much like elephant ivory but tremendously harder. Fossil bones & tusks are always an option but it's a crapshoot getting solid stuff & it's a very expensive gamble.
Hope this helps. Be ready for a lot of time & money learning what is good, what is not, and getting usable parts from any of it. Nothing looks quite like the genuine bone & horn but there's a price to pay for that look. Also wear a good mask. This stuff is organic, some extremely old, and carries all kinds of nasties for your immune system. Trust me, if you cut much you'll get sick.
