Hi. Thanks for your interest. I started Tom Thumb but stopped. :( I'm not that familiar with ZX81, although I've watched the MAZOGS game, but I should get familiar with it. :) I'm currently working on a pretty big project that's coming out next month and I'm rewriting Wizard's Lair.
The recent issue of Retro Gamer (Issue 264, fittingly enough) had a "Minority Report" section focusing on lesser-known games for the Commodore 16. Games mentioned are Tom Thumb, ACE, Voidrunner, Squirm, The Magician's Curse, Monty on the Run, Kikstart, Zagan Warrior, Legionaire, Fire Galaxy and Summer Events. Oh, and the "Retro Stinker" they picked was the lousy C16 port of Green Beret.
I also think you should also look into games for Bally Astrocade, Dragon 32/64, Mattel Aquarius, Oric Atmos, VTech CreatiVision, Acorn Atom.