Not exactly "more variety", but my Must Use mods are:
Free camera rotation
Numeric Health Display
Perfect Information, so you can get even more depressed.
Always Show Shot Breakdowns. The tabs closing because why not should have been fixed in the last patch, but I didn't have a chance to test it.
Stop wasting my time, even with ZIP mode there.
True retroactive AWC, because fuck losing the extra skill on that lucky guy that survived from the start.
Smarter Sectoids, because fuck me. I don't feel comfortable with how stupid vanilla Sectoids are.
Beatdown skill. A life saver. And beating down aliens never gets old.
Full customization from start
Lifetime Stats. So you can create appropriate epitaphs for your truly useless soldiers.
World Expansion Project: ADVENT and
More maps packs. Even more terrain variety.
If you use the Action Cam mode,
Clean Cinematics.
And around 5150347 aesthetic mods with uniforms, armors, helmets, fancy horse hats, camouflage patterns and so. Just take some time to do a pass around and suscribe to anything you may like, is really worth.