As far as Garfield games go, one I would like to give a second chance to is Garfield: Caught in the Act. It was only on SEGA Genesis, so I never played it much, but I sure wanted to. When I did play it through emulation, it wasn't quite as good as I hoped, but it wasn't THAT bad either. It was also made during the peak of 16-bit 2-D sprite art and animation, and I even read somewhere that Jim Davis himself did the illustrations for the graphics. I wouldn't mind a re-release or maybe even a remake with some gameplay tweaks and quality of life features.
As far as a Heathcliff game goes, I'd like to see a game based on the cartoon. More specifically, the Catilac Cats portion of the show. It's the part where these three junkyard cats would travel in their transforming car/boat/plane and have all sorts of adventures. That was my favorite part of the Heathcliff cartoon!