Pathfinder: 24%
D&D 5E: 20%
In Q4 2021:[2]
D&D 5E: 55%
Pathfinder 1E+2E+Starfinder: 5%
Pathfinder 1E, 2E and Starfinder all rely on OGL 1.0a content.
1: https://blog.roll20.net/posts/the-orr-group-industry-report-...
Roll20 still has the overwhelming supermajority of the VTT market, Foundry is the Linux of VTTs.
Some of us use d&d beyond with it, some not. I think the dungeon master prefers foundry much more than roll 20.
What it took was the dungeon master saying we shall do this, a session or two to work out the kinks, and one other player who gained expertise enough to explain game play mechanics (e.g., use the x key) to the rest of us (to offload some of that burden from the dungeon master)
Foundry: 7
Roll20: 7
Unspecified: 2
Fantasy Grounds: 1
Discord only, no seperate VTT: 1
Owlbear (never heard of this one before): 2
D&D 5e: 51.87%
Uncategorized: 14.27%
Call of Cthulhu: 9.48%
Pathfinder: 6.46%