I've got 3Corys and a dwarf Pleco in my 10 gal, they are great, add so much character to the tank. Started off with 2 Corys and added a 3rd couple of days ago - thought the others were going to isolate him as he spent ages all on his. Noticed yesterday that they're all swimming around like best of friends.
One of my fav's though is the dwarf pleco, amazing algae eater - Saw him other day stuck on the inside of the outlet to my filter cleaning that up, every now and then he would lose his suction come shooting and then work his way back in again. He's also won Hide & Seek on any number of occasions, he's an absolute master at chamouglage