Dustbiters expansions
Kind of.
This cheeky and nitpicky "expansion" is really just three cards from the original 21-card game that were selectively removed from Button Shy's "Pocket Edition" to maintain their 18-card standard, then sold separately as an add-on. The horse and bike are at least distinct enough to feel expansiony, then there's another truck. There's no reason you wouldn't want these to complete your abridged game.
Rustlicker's Convoy solo variant ****
Seeing this fan variant on BoardGameGeek was more incentive to buy the game that probably doesn't suit my six year old's level or taste. It's carefully fiddly in the automa's favour, so it doesn't waste too much time doing stupid and self-destructive things, and it wins by chance often enough to be satisfying.
