Colossal Cave Adventure, (1972) - The first Text Adventure game.
pedit5, (1974) - The first true digital RPG. It was text-based.
The first MUD, (Multi-User Dungeon), game was released in 1978. It doesn't have a name other than MUD.
Adventure, (1979) - Considered the first Action-Adventure game. Released on the Atari 2600.
Akalabeth: World of Doom, (1980) - The first graphical computer RPG and first commercially released RPG.
Dragonstomper, (1982) - The first console RPG. Released on the Atari 2600.
MAD, (1984) - The first global MUD.
Islands of Kesmai, (1984) - The first MMORPG.
Dragon Quest/Warrior, (1986) - The first JRPG.
Neverwinter Nights, (1991) - The first graphical MMORPG.