I discovered MUs early on in life as many of us did - and it's influenced the kind of TTRPGs I've bought for years, thinking this or that might make an interesting MUs experiment or, they were games that my local group didn't have an interest in/time for.
Sadly, I've never touched a good 90% of them, so I thought I'd list my top few and see what others had sitting in their mental/shelf queue/wishlist!
To me, this is more of a SYSTEMS conversation than setting - but both are welcome! Also, chime in if you'd tried a ruleset and its level of success. Please try to be constructive about it, though!
Atomic Highway/V6 System has been sitting on my shelf for a long time, as one of those games that I'd potentially like to see how it worked out. System and setting. I a good Mad Max setting.
Dragon Ball Z RPG/Instant Fuzion. I always thought this system/setting would be amazing for LOLs (and a nice break away from Ansty Games). Plus, I think Online is the only place where you can obtain enough dice for some later powers. Problem: Running out of planets eventually.
Jadeclaw Alas. I don't think I'd ever really been able to handle the crowd it would attract.
Tunnels & Trolls I've always enjoyed how simple MOST of the rules are for this game. Originally made as a solo RPG, I've always thought this would make a good hybrid game or an L&L that needed a quick, GMless combat system.
Mekton Zeta/MTS Because we all need more giant robots in our lives. Though this one, I think is just a matter of time for me. I have a hankering for some Mecha based Space Opera in my life.
Inspired by the MU*s That we Would Love To Make (But Won't)