Which direction does it face...
North or east facing you can do mint parsley and the light leaved sages and chives but if you want to do anything else you need to increase the light perhaps by putting foil on the wall behind the pots.
South or west facing rosemary, oregano, thyme, parsley, sage, chives and garlic best to put the pots in a tray of gravel and keep everything well watered perhaps use a wick irrigation system
Also try nasturtiums for the edible flowers and a pot or two of baby salad leaves
If your balcony is very exposed you may need to consider some form of wind protection you can get special fabric for this looks like a dk green loose woven mesh or put your herbs among a few taller plants