Violets (and pansies and jump-ups) come in many colors, each with a different taste.

Ground ivy (Glechoma hederacea) flowering tips are delicious in salads.

Red maple flowers are a gourmet treat.

Cherry blossoms, apple blossoms, peach flowers too; all the rose family trees provide flower petals rich in vitamin C.
(I shake them loose after they have been pollinated.)