A group of 6 tiger barbs would look great.
If you really like them you could go with 10.
Some other options are....
2 Angel fish 3 swordtails
Platies
Gouramies
5 male guppys 8neon tetras
Britlenose pleco
Siamese algea eater shark
corydoras
Silver dollar's
Khuli loaches
Weather loaches
Danios
Ghost shrimp
Just if you ever decide on any of the fish suggested learn about what their needs are first and make sure size is ok for your tank.... Like don't get TONS of fish