There's a .opk of The Ur-Quan Masters for OpenDingux, and it's on Portmaster as well. Source is available from https://sc2.sourceforge.net/, and there's an extended "megamod" from https://sourceforge.net/projects/uqm-mods/. This is one of the best games ever made, it's completely open source, and getting it ported into Onion would be a big win. It's already ported to Linux, and to libretro, and should just need repackaging work.