Another good one is Act Raiser, which combines elements of Sim City with an action platformer. Then there's E.V.O. which is an action RPG based (losely) on the concept of evolution. There's also Super Mario RPG: Legend of the Seven Stars but that game alone gets so much discussion it's almost not worth bringing up. I also have a distinct fondness for Soul Blazer as it was my first SNES action RPG. Paladin's Quest was a well known game back in the day, but I can't speak to its popularity, and I'm not terribly fond of it either. Finally there's The 7th Saga, which is often creditted as being "the hardest RPG of all time ever." I never got that far in it so I can't really speak on its difficulty.