Вообще основная серия это Might and Magic:
Might and Magic Book One: The Secret of the Inner Sanctum (1986; Apple II, Mac, MS-DOS, Commodore 64, NES, MSX, PC-Engine CD-ROM²)
Might and Magic II: Gates to Another World (1988; Apple II, Amiga, MS-DOS, Commodore 64, Mac, Genesis, Super NES (Europe only), Super Famicom (Japan-only, different from the European Super NES version), MSX)
Might and Magic III: Isles of Terra (1991; MS-DOS, Mac, Amiga, Super NES, Genesis (prototype), Sega CD, PC-Engine Super CD-ROM²)
Might and Magic IV: Clouds of Xeen (1992; MS-DOS, Mac)
Might and Magic V: Darkside of Xeen (1993; MS-DOS, Mac)
Might and Magic: World of Xeen (1994; MS-DOS, Mac)
Might and Magic VI: The Mandate of Heaven (1998; Windows)
Might and Magic VII: For Blood and Honor (1999; Windows)
Might and Magic VIII: Day of the Destroyer (2000; Windows)
Might and Magic IX: Writ of Fate (2002; Windows)
Might & Magic X: Legacy (2014; Windows, OS X)

А Heroes of Might and Magic - это спин-офф
и мне предельно не понятно зачем создавать новые миры с открытым миром вместо того, чтобы сделать ААА M&M