MYST and
Quake (Clickboom version) were sold as commercial games... and there are many commercial games converted/ported from MS-DOS. But from different perspective
Quake is also open source conversion.
Other thing is Quake II. Sure, there's commercial version, but only for PPC. 68k version is only open source conversion.
Rise of the Triad was mentioned already
BTW: No caps?