Pulling together all the UFO variants that existed in mods was gzegorj's project with YetMoreUFOs. Unfortunately, he seems to be on a break now :/
He did a great job of bringing UFOs from Luke's Extra UFOs, Solarius' new UFOs (types) and some other resources I don't know of together, and patching them as he was going through them. It's really a shame he never managed to get through it all, as his mod was a great addition to any campaign that depends on vanilla UFO type.
You could have any other mod activated, as long as what it referenced were UFO the basic UFO types (small/medium/large scouts, terror ships, etc.) without adding to it, enabling YetMoreUFOs as a companion allowed to get all the variety. Too bad he's gone, really.. If someone wants to pick up that project, it would be great for the community. I can't, mapview refuses to run properly on my linux computer (or at least I am not proficient enough to convince it to)..