You can try chinese cabbage although I have generally had limited success with those. Some recommendations.....
Easiest and most abundant: Komatsuna, Senposai, Mizuna
Hardy: Tatsoi
Mustard: Green Wave Osaka Purple are good
Flowering stalks (think broccoli): Kailaan, Choy Sum
Mild tasting leaf radish: Saisai
Mooli radishes (daikon)
Not chinese exactly but good greens: turnip greens (any turnip produces tasty leaves or the itallian equivilent Rapa Senza Testa
And don't forget real spinach for sowing late july/august for wonderful tender leaves in the autumn and well into the winter.