Orchard Bark, Coconut Husk, and Cypress. Cypress can be hard to find, and I seem to recall some of it comes from the south east US and causes issues. Someone else is bound to know the in-depth, but it's something along the lines of trees that are supposed to be there to help break up hurricanes are being removed, leading to more dangerous landfall of hurricanes, and it's harming the environment.
Orchard Bark and Coconut Husk are highly recommendex, I'd not suggest EcoEarth for ball pythons, I use it for my rats, bugs, and as a mixture with dirt and sand for my lizards, but as stated above it can get in the snakes mouth and cause issues because it's such a fine substrate