Barbs are feisty by nature, though cherrys usually are calm. But to avoid risk, and with gourami, the rasbora group offers several suitable species. Honey Gourami
are one of the calmest and most peaceful of the gourami, though still a "gourami" by nature. If you read our profile (click the shaded name) it says they will work as a small group in a 20g or larger tank, so I would add a couple more if you like them. Plant it well, esp with floating plants (gourami need floating plants) and except when spawning things should be quiet.
Then a group (7) of one of the rasbora, just not the dwarf species that are very tiny. The three similar species in the Trigonostigma genus are good; very peaceful, colourful, mid-water, and they remain together as a group more than almost any other freshwater species. All three are in our profiles. Dwarf Gourami
would not be good at all, for reasons noted in our profile. Plus, as soon as you introduce a second gourami species to any aquarium, you are entering into territorial disputes among them. Cichlids (angelfish) were mentioned somewhere in this thread, they too are not advisable with gourami, but in this case the tank is too small for a group.