It would really be good if someone could provide an updated overview of all of the "GCs for Rust" created thus far -- for a while I tried to keep up with them, but there are just too many! When we wrote the Alloy paper, we took Manish's survey as a starting point, and covered as many GCs of different kinds as we could squeeze in [1]. But even then there was no way we could squeeze _everything_ in, and I've seen at least 2 or 3 new ones since (safe-gc is older than the Alloy paper, so I'm not including it in that count)!
[1] https://soft-dev.org/pubs/html/hughes_tratt__garbage_collect...