I run games for a couple of obscure platforms—mainly the MSX—and I often wish that there was a forum specific to the platform rather than any individual game to ask questions pertaining to the platform in general. Like, if a platform is known to have emulator settings or particular hardware models that aren't good for accurate runs, it would be nice to have a central place to look for that information, rather than trying to figure it out for each individual game.

It would also be nice to search for recent runs by platform, in order to find the games for each platform that have an active community. You can search for games by platform currently, but that doesn't distinguish which games have runs specific to that platform. Most of the games listed for MSX, for example, are classic games that were released on every platform ever, but have never been run specifically on MSX, so it doesn't really help me when I'm trying to find MSX-specific information.

You could create a discord server. For mobile games we have the mobile speedrunning discord and even though that platfor has many games the discord still works specially for small games. If theres not many games you can even make separate channels for each game for that platform but if the platforms and the games arent too popular then it will still be useful

I know that issue. I'm running a couple of retro games and wanted to find someone who can help me with getting a NEC PC88 game to run... without success so far. I'm actually in a couple of discords with other retro-runners. But those guys are doing NES, Amiga, DOS,... games which are the more popular retro consoles. It is actually hard to find experts on that matter and a personal discord won't cut it. If you know how to advertise for this it can work possibly I guess.

A centralized forum on a big site like SRC wouldn't need much work to get attention in the first place.