Can we please make this the off-topic icon?
fas fa-film Since I got in first I should get to pick it! 😀
AwesomeAdmin The forum software of our choice is Flarum, a great and light-weight alternative to Discourse and NodeBB.
Discourse is very different really, Flarum isn't an "alternative" to it at all it's a different type of forum software. Most notably Discourse has a tech stack that no one really uses, doesn't play well with virtualisation, and is target towards corporate-type websites.
As for NodeBB I can't even think of a live-example I've ever used (not surprising when it's still in Beta). Its UI leaves much to be desired, it's basically like the OLD Discourse except that it's written in NodeJS. The most powerful forum software, almost by an order of magnitude, is XenForo - but it's commercial and closed-source (though it would work out a LOT less expensive than Discourse even if you tried to self-host TBH).