This is interesting. We ended our game last night about 7 and were setting up the TV for the MNF game (Bills crushed the Titans) and we started critiquing last night's D&D game and we got on the topic of playing 2E. That was so many years ago I forgot all the non d20 nuances as far as dice mechanics went. That was a time when I would spend a lot of time coming up with character concepts. Kits were great and I'd like to see those come back. But Im surprised that Roll20 is supporting these editions now.
It's pretty understandable, what with all the chatter about OSR games and "the way D&D used to be" on the Internet.
Roll20 Supports AD&D 1E, AD&D 2E, D&D 3.5E, D&D 4E, and D&D 5E. They still don't have official support for B/X, BECM, or RC, but I'm optimistic that it'll be added eventually. As for OSR games, Roll20 supports Basic Fantasy, Labyrinth Lord, Swords & Wizardry. It also has a generic "OSR" category that contains a lot of the tools and instructions for setting up nearly any retro-clone...and I've used those tools to set up a BECM game with my high school buddies a while back.
And the list of non-D&D games supported on Roll20 is extensive: BESM, Call of Cthulhu, Chronos, Covert Ops, Cyberpunk, Cypher, D00 Lite, Dark Heresy, Earthdawn, Esper Genesis, Fate, Fate Core, Fading Suns, GURPS 4th Edition, OneDice, Pathfinder, Savage Worlds, Shadowrun, Star Frontiers, Star Trek, Star Wars D6 and Star Wars RPG, Starfinder, The One Ring, Tinyd6, Traveller 5E, Vampire the Masquerade 5E, Warhammer, World of Darkness, and about a dozen more that I didn't even recognize.
I think Roll20 is a lot bigger and more versatile than folks give it credit for.