There has been several implementations of Forth that were running on, and targeting, the C64. Were there any commercial software releases (not throw-away hobby projects or in-house utilities) that were implemented in such a Forth system? The more widespread the better; my favorite would be if there was a released game.
Amnesia (Electronic Arts) is probably the most famous one. The King Edward Adventure Game system was just a wrapper.
Hard Hat Mack (Electronic Arts) copy-protection was written partially in Forth.
Among educational titles, Davidson and Associates published a few, like Alge-Blaster and Read 'N Roll.