Tons of different options! I have a 20 gallon tall that is similar in proportion to a 10 and is stocked with cherry barbs (which are quickly becoming one of my favorite community fish), several varieties of danios (zebra, albino, leopard and longfins of all 3, and purple passion danios as well), and porkchop rasboras. All are CHEAP, readily available community fish. I've come to love my danios even though a ton of people hate them because they're super common, as they're always moving, have awesome patterns, and have a great variability. Just looking at one of each type of the common ones, you have- zebra, albino zebra, leopard, longfin zebra, longfin albino zebra, and longfin albino. That's 6 different fish, and all are the same species & will school together. A 10 gallon could easily support a school of 8-10 danios, 5-6 cherry barbs, and maybe even a couple porkchop or harlequin rasboras.
You could also add in a couple dwarf cory cats as clean up crew.