Old, old school AD&D 2E, One of my current campaigns has been running for over 20 years. I started with the pamphlets & went to 1E then 2E, and 5E.
Currently running: Stars Without Number, AD&D2E, Cthulhu Confidential Gumshoe One2One, Pathfinder 2 playtest, Trail of Cthulhu, Night's Black Agents, Amber Diceless
Audio: Discord https://discord.gg/KkR3nzF
Video: As Appropriate (Gumshoe)