The cories would be happier with more of their friends but if you want variety I think you could add one honey gourami without much issue. Not to many other fish you can add, 10gals are pretty limited, esp with adding cories sadly.
For example, my gf's 10gal has 3 priscilla tetras, 1 honey gourami, 1 mystery snail. Thats pretty much fully stocked.
40Gal Planted- 10Gal RCS Planted
6 Julii corys, 1m Furcata Rainbows, 2f 1m Bose Rainbow, 2 mystery snail