What does the USFWS not allow other than lead?
I don't know what the USFWS has refused as I am not privy to what is offered to them for their approval. I do know - through actually reading the regulations - that the only shot types one is allowed to use for waterfowl (and therefore upland where required) are those approved by the USFWS. As I was very active in waterfowling back then I do recall through that time reading of, then using bismuth, tungsten/iron, and tungsten/polymer shot in Canada (and South America though I hadn't hunted there) and the subsequent write ups in various hunting mags pushing for USFWS approval.
For the edification of all, approval prior to use for a given shot type is needed is due to the requirement that said shot type must not cause sickness or death in waterfowl. Therefore, each proposed non-toxic offering needs to pass testing on that subject. That is why there is a listing in the waterfowl synopsis of what materials are approved.
