Small gobies and sexy shrimp for stocking suggestions.
Advice: don't do it, lololol. I've pretty much given up on mine because of the lighting. If you plan on doing more than really low-light softies for coral, good luck.
Edit: Response to above:
You can do corals, you just need to do small adjustments and have low ambitions. They're not that difficult to clean unless you have a large amount of rock or huge hands. The filter is the most widely suggested HOB.. And a lot of people don't think a 6 gallon needs a protein skimmer.
If you are reasonable with your intentions for the tank, it's not bad. But if you want high light corals and big fish, don't do it.