D&D 3.0: Tales from Mystara
Classes: Half-Elves can be of any class that Elves-High or Humans can but many of them prefer to be Bard and Sorcerer.
Mystara Locations: Wherever there are Humans and/or Elves-High present there could be half-elves. Places prohibited for Elves like the Broken Lands and the Kingdom of Rockhome are also difficult for half-elves to be.
Social Class: Because of he stigma of been a mixed race, the Half-Elves can never be of a Social Class higher than Wealthy/Untitled, any roll result higher must be lower to that social class level.