You should be able to grow most of these, particularly in larger pots:

Pentas, dahlias, cape plumbago, iris, mallows, ageratum, chrysanthemum, osteospermums, lysimachia, salvia, scaevola, lantana, alyssum, scabiosa, verbena, anagallis, astroemeria, bacopa, callas, clivia, cannas (big pots), convolvulus, daylilies, erysimum, euryops, lamium, gazania, dianthus, geraniums, pelargoniums, hellebores, heuchera, impatiens, lavendar, lotus bertholotii, snapdragons, mimulus, nierembergia, bluett (centaurea montana), pieris, ranunculus, dwarf rudbeckia, common garden sage (it has lovely spikes of purple flowers and will rebloom if you deadhead it), gazanias, tulips (but they'll need chilling if you want them to come back).