Table S3 here[1] starting on page 9 appears to show nearly 80 different genuses within stool samples after filtering out "vegetative (non–spore form) bacteria, fungi, parasites, and viruses" [2].
No word on how many strains per genus, but reasonable to assume multiple, if not hundreds in some cases.
On nice! I will save that one and read up on each species. I think it would be useful to know which of those are beneficial and are missing from the 20 I utilize.