Cocobolo, Tulipwood (which isn't from tulips), certain Central American rosewoods and Kingwood are all dalbergia genus woods. They're dense, oily, resinous and the resinous dust is VERY irritating. Wear a mask when working it. At the very least a paper one. One of the filter types is better.
Some people are allergic to the resin or dust. It's hard to seal properly without catalyzed vinyl or epoxy--they're so tight a grain and so oily that most finishes flake off. I generally don't finish them, just polish them down to 320 grit or so and wax.
Purpleheart, Bloodwood and Padauk also are irritants in a similar way. The more open woods, like bocote and zebra wood are less so, but still can be. Wear a mask when working with ANY tropical wood, or ivory, bone or horn.
And I recommend against ever using imported bone, or human bone. There are perfectly legal sources for both, but you have no idea what killed the animal/person and some of those diseases sporulate in bone.
There are some excellent burls of maple (actually smells nutty), walnut, ironwood and the laminated birches (Dymondwood(r) and Pakkawood(r)) that are almost guaranteed allergen free and are far less irritating.
G10 and carbon fiber REQUIRE a respirator type mask to work if you don't like the hospitality of your local hospital. But they're fairly benign once finished.