not a gm but in a game I play in they use www.owlbear.rodeo and I don’t think it costs anything and is pretty nice. its a play by discord. between that, wanders guide, and the kobold discord add on it pretty much covers everything.
Foundry VTT, Dungeondraft, whatabou dungeon generator, Mork Borg DUNGEN and monster generators, Procreate for drawing dungeons, Stable Diffusion for images I can’t find, various character generators/builders for whichever game I am running.
Most useful: pf2easy
Foundry VTT (Hosted by Forge). We play in person but it’s still good. It works well and has super pretty maps, but we only use it as a map, not the advanced features. Also takes a LOT of resources, a shitty tablet or old laptop might not keep up. Not super intuitive and hard to use with a touchpad/touchscreen. I stoll recommend it though :P
My players use Pathbuilder.
Oh and AoN of course, but pf2easy is usually faster.
I haven’t played online yet, and I certainly haven’t GM’d a virtual game. But it’s interesting how the same tools are coming up in both the online and offline posts.