Before Origins Online was cancelled, it did put up a full listing of events, which were planning to use an amazing variety of platforms. Most of this list comes from that, with one thing added that I only ran into at one of the Paizo cons.
For panels, workshops, and free-form RPGs: Discord, Twitch, Zoom, Facebook Live, Skype, GoToWebinar, Crowdcast, YouTube, Google Meet, Google Hangouts, Lifesizecloud.
For board and card games: Board Game Arena, Tabletop Simulator, Tabletopia, VASSAL aka Vassal Engine, untap.in, OCTGN aka Octagon, Astral TableTop, Miro, plus some games have their own dedicated online implementations.
Discord is also used to supplement many of these with voice and/or text chat.
For highly structured RPGs: Roll20, Fantasy Grounds, Google Slides.
Discord is used for voice chat (and text in the case of Google Slides). Roll20 and Fantasy Grounds have their own integrated text chat which is sophisticated enough that games on those platforms use it; Roll20 has also offered voice chat for a while but I've yet to attend a game that used it.
For panels, workshops, and free-form RPGs: Discord, Twitch, Zoom, Facebook Live, Skype, GoToWebinar, Crowdcast, YouTube, Google Meet, Google Hangouts, Lifesizecloud.
For board and card games: Board Game Arena, Tabletop Simulator, Tabletopia, VASSAL aka Vassal Engine, untap.in, OCTGN aka Octagon, Astral TableTop, Miro, plus some games have their own dedicated online implementations.
Discord is also used to supplement many of these with voice and/or text chat.
For highly structured RPGs: Roll20, Fantasy Grounds, Google Slides.
Discord is used for voice chat (and text in the case of Google Slides). Roll20 and Fantasy Grounds have their own integrated text chat which is sophisticated enough that games on those platforms use it; Roll20 has also offered voice chat for a while but I've yet to attend a game that used it.