Since no one else has replied, I'll give you a full list! (I have a list addiction.) I am one year older than my brother and was a little more into MOTU than he was. He was a little more into G.I. Joe than I was, and we were both equally into Transformers. As a result, the list of MOTU that I owned is longer than his.
Mine were: He-Man, Prince Adam, Battle Cat, Orko, Skeletor, Battle Armor Skeletor, Terror Claws Skeletor, Moss Man, Ram Man, Man-E-Faces, Mekaneck, Stratos, Roboto, Rokkon, Whiplash, Jitsu, Stinkor, Two-Bad, Webstor, Screech, Dragstor, Leech, Mantenna, Modulok, Orbear, the Wind Raider, the Slime Pit, and Castle Grayskull.
His were: Beast Man, Kobra Kahn, Mer-Man, Tri-Klops, Trap Jaw, Man-At-Arms, Fisto, Sy-Klone, Buzz Off, Extendar, Hordak, King Hiss, the Attak Trak, and Stridor.
We shared the Fright Zone, and our little sister owned Teela and Grizzlor (she wasn't into MOTU, but asked for Teela so she could play with us occasionally, and asked for Grizzlor because she wanted to comb his fur. She was more into Barbie and Strawberry Shortcake. Too bad.)
I have a lot more nostalgia for the figures that were mine, but I'm still very drawn to the figures he owned that I *wished* were mine...like Kobra Kahn and Trap Jaw. Most of my memories of playing MOTU are of me playing with neighbors or by myself, but not my brother. When he was involved, we usually played GI Joe or Transformers. He wasn't really into magic and storytelling. That's pretty much ALL I was into, lol.
We moved to a small, secluded town for a while in 1986 and mostly lost track of MOTU (except for one evening, when we found Dragstor and Extendar at our local supermarket). When we moved back to the city, we were all about Transformers. I missed the later years completely. Hadn't even heard of Rio Blast until a few years ago. New Adventures was a complete surprise to me. It's been a lot of fun, discovering what I missed back then.