10 gallon bottom feeders

[dmnddog02]

Hello all. I'm quite new to aquarium keeping and have had a successful 10 gallon for about a month with 3 male guppies and 1 female betta. I'm wondering what sort of bottom feeders would fit into my setup? My substrate is larger gravel if that makes any difference. Thanks!

[Aiken Drum]

Pygmy cory?

Edit: possibly not with your substrate