Define good looking, and not expensive. If your limitation is under 30 dollars, and needing color, or different patterns from commons, then you are out of luck.
Lots of striped smaller Panaques and Peckoltia you could get, probably get some Hypancistrus with that, maybe some Leporacanthicus species... theres a couple to choose from, hundreds more.
L02, L129 should also fit your requirements. Ancistrus certainly can also be great in a 40 gallon tank, usually staying 6 inches or less, omnivore so can go well with many other plecos.