Hussar
Legend
Stoat - I haven't played those games, but, I suppose the Baldur's Gate would be an example too. The main plot basically only advances when the player chooses to do it. Otherwise, you can wander around, doing a plethora of side plots as long as you like and the main plot will wait on hold until you come back.
Agreed, this runs contrary to how I view a sandbox campaign as well.
Agreed, this runs contrary to how I view a sandbox campaign as well.