Almost everything on our plot is an edible crop, and that includes a lot of flowers. Nasturtiums as already mentioned, pansies & violas, violets, small flowered begonias, pinks & carnations, chives, dahlias, calendula, roses, borage, primroses, lavender, rosemary, thyme, cornflowers, french marigolds, sunflowers of all shapes and sizes, wild garlic, daisies etc, plus of course the bean & pea family ,which has gorgeous flowers in their own right.
I hope that gives you a few ideas... the insects will certainly thank you! Mainly, our flowers are grown in strips at each end of the beds, so they are interspersed with the "green" crops and it looks attractive, as well as attracting masses of bees and other insects