Suggestions for a 30 long tank

[kdx7214]

I was unexpectedly given a 30L tank, complete with stand and LED lights today. I had no plans for another tank at this time, so am trying to decide what should go in it. I'm considering making it a home for my more aggressive fish (like the six line wrasse). Anyone have suggestions for what would go well in this size tank?

 

[bushdoc]

I have Pistol shrimp/Watchmen goby pair, two Pajama Cardinalfish and Pygmy perchelet AKA Geometric Goby and they all seem happy and coexisting. You can probably add bit more.