Xtrac wiki is the only one out there. Another organized kind of database related to Outerra are sites for mods, there are a few, but that's about it. Lack of wiki-ish resources for Outerra can be explained easily: there aren't much systems in the engine/game right now, systems in the most basic meaning of that word. Take for example any early-access platforms or games, like Rust (might not be the perfect example, but that is the first thing that came to my mind). It has lots of mechanics and entities that are worth writing about and full description of which isn't accessible within the game. On contrary, Outerra doesn't really have much of that. All you need is the hotkey panel to know how to do certain things like spawning stuff or changing environmental parameters. For more complex stuff like scripting and whatnot we have xtrac.
I'm not against more user-friendly wiki, it would be neat, but there is also not much necessity in it as of yet.
