Visible pen strokes. Somebody sat and drew every frame. Makers apply this tag to their own games, so this is a room full of things that set out to feel a particular way, and mostly manage it.
The tag exists, the games have not turned up. Tags get applied by makers at submission, so this fills in as people ship.
Tags cut across the catalogue; categories divide it. If Hand drawn is not quite the cut you wanted, one of these twelve probably is.