Calla lilies, roses, chrysanthemums, carnations and tulips are all available in yellow. Calla lilies are nice alone in bouquets with only a ribbon tied tightly around the stems. Roses and chrysanthemums are lovely with white accents like white mums or carnations. If your color scheme is only yellow, add some greenery or baby's breath to fill in the bouquet.
Black Eyed Susans in all their varieties are beautiful sturdy yellow flowers. They are wonderful long lasting cut flowers and would be great for a wedding. There are yellow asters, chrysanthemums, daisies and many others. Try going to a florist and finding ones that don't have odors that may be too strong before you make a final decision.
Yellow flowers include daisies, chrysanthemums, lilies, daffodils, marigolds, iris, azalea, poppies, sunflowers, tulips, and, of course, yellow roses. Yellow roses or lilies would probably be the best wedding flowers.
There are lots of yellow flowers available in the market:
Roses, Fuji Mums, Tulips, Poms, Gerbera Daisies,Mini gerbera daisies, Onicidium Orchids, Cymbid Orchids, Solidasters, some hyperiums when they still "young" their berries are kinda yellow.