Cool fish combinations for a 20g long tank?

I want it to be a community tank, I really like all types of fish but my favorites are cories, barbs, gouramis and tetras. I have asked if i can keep them together in a 20g long and i got all no's. Any other combinations for a 20 long. i will take all community combinations. And could you also give me links to the type of fish you guys reccomend? I want to pack my brain with info on fish :) Thanks!