Cory cats may do
best in groups of 5 or more, but I think three of one variety would be fine in a ten gallon. Shyness seems to vary by species, as my peppered corys are not at all shy, with me or with other fish, and my bronze corys are quite skittish. They also don't grow to full size all that quickly, and they stay at the bottom of the tank, so if you have a good filter and do regular water changes, it probably wouldn't hurt to have some hardy mid to upper level fish -- a small school of a peaceful species that doesn't get terribly large.
Some possibilities include a variety of smaller tetras such as head and tail light tetras, black neons, black phantoms, serpaes, or a peaceful barb like the cherry (keep in pairs with lots of plants), or the harlequin raspbora.
Alternatively, you could go for one or two more striking fish -- such as one betta, one Paradise Fish, or a couple of dwarf gourami. The choice is yours, just keep the tank clean and stay away from fish that get big!