I'm not sure what "switch-appropriate" means in this context.

Also not sure if you mean forums running nodeBB specifically or just any forum. I'm on a few, mainly for worldbuilding and constructed languages. The CBB forum and The ZBB. There's a lot of overlap in user base between the two, though I prefer the former. Both run phpBB. There's also Anthologica which is running custom software with features that cater to the conlanging community. I attempted to make a nodeBB instance for these topics, which is why I have an account here. But I decided that the hobby was too niche to risk spreading it thinner.

I hang out on some video game forums too. The Minecraft Forum is a shadow of what it used to be when the game was in beta. I was just on The Terraria forums yesterday. I apparently don't have an account there but I can swear I posted there back in 2012.