What kind of fish should i get in my 10 gallon aquarium?

i have 7 fish which i have 4 black mollies, 1 guppy, one sucker fish, and one neon tetra. they all get along just fine and i was wondering if i could fit one or two more fish in my aquarium. I wasnt sure if i should get another neon tetra to keep my other one company beacuase i herd they need at least 1 other fish of its kind. So, please help me! thanks!