Gargoyle's suggestion of minnows (the white cloud mountain minnows are pretty fish) and livebearers (guppys or platys would be my favorites there, but there's also swordtails and mollys) is great and Zebra Danios are very hardy.
The White Cloud Mountain Minnow only get to 2" but like the water cooler than many other fish.
Zebra Danios get to about 2", but 6 or more are recommended to keep them behaving better with other fish.
Livebearers like to have 3 or more of their own type and if you don't want babies, get all males:
Guppys get to 2" usually. The neon blue guppys are especially nice but bigger than other guppy types (3")
Platys get to about 2" and great fish.
Mollies get to 2-4" and we really like the dalmation mollies.
Swordtails are the biggest livebearers at 5".
You can really get any number and combination that you want, but the general rule is 29" of fish for a 29g. Livebearers will breed like crazy if you get any females and all of the fish above will show more schooling behavior with more fish of that type.