Is there a good overhaul mod for UFO, something like what Long War was for Xcom?
There's also The X-COM Files, which is Final Mod Pack++, has a number of new features. The big gist of it is that its a "prequel" of X-COM, you start the game as a bunch of Mulder & Scully types with a lot less resources and backing, investigating the aliens and such, fighting cults, monsters and infiltrators, learning, fitting pieces, obtaining authorization for more equipment, until you become the X-COM from the games, then you continue your game from that point onwards until Cydonnia.
Its still in beta, but its hella fun! I did a short-lived LP of it, but sadly a change of imagehosts took it down.