Most lists of nectar plants are not very comprehensive, or consist only of temperate perennials, of which I have very few. I've been compiling a list from variously located scholarly sources, watching documentaries, looking at the flowers hummingbirds and b'flies are visiting in pics, and including tropical plants that are considered house plants outside of their natural regions but known as a nectar source. The more I realize how many nectar-producing plants there are, I will not add any more plants to my yard that do not fit this category. Not all b'flies or hummers would visit every plant on this list, and I tried to weed-out any synonyms but there may be a few for plants I'm unfamiliar with, a common name added when found or known, though I'm sure some of these plants have others. Anything else seen being used as a nectar source?
Acanthus
Achillea, yarrow
Aeschynanthus, lipstick plant
Agastache
Aguilegia formosa, western columbine
Alcea rosea, hollyhock
Alstroemeria, Peruvian lily
Angelonia
Antirrhinum, snapdragon
Asclepias tuberosa, butterfly weed
Asclepias, various, any = milkweed
Aster
Begonia
Buddleia, butterfly bush
Calibrachoa, million bells
Campsis radicans, trumpet creeper
Cannas
Ceanothus americanus, New Jersey tea, CA lilac
Centranthus ruber, Jupiter's beard
Cephalanthus occidentalis, buttonbush
Chrysothemis pulchella, sunset bells
Clematis heracleifolia
Clematis virginiana, virgin bower
Cleome
Coleus
Coreopsis
Crocosmia, cardinal flower
Cuphea, cigar flower
Dahlia
Delphinium
Delphinium, larkspur
Dianthus, pinks, sweet William
Dicentra spectabilis, bleeding heart
Digitalis, foxglove
Eupatorium, Joe pye
Fuchsia
Gladiolus
Heliconia
Heliotrope
Hemerocallis, daylily
Hesperaloe parviflora, false yucca
Hesperis, dame's rocket
Heuchera sanguinea, coral bells
Hibiscus syriacus, rose of Sharon
Hosta
Hoya
Hyssop
Impatiens balsamina, jewelweed
Impatiens capensis, jewelweed
Ipomoea coccinea, red morning glory
Ipomoea multifida, cardinal climber
Ipomoea purpurea, morning glory
Ipomoea quamoclit, cypress vine
Jasminum, Jasmine
Justicia brandegeeana, shrimp plant
Kniphofia, red hot poker
Lantana
Lavendula, lavender
Liatris
Lilium, Lilies
Lobelia cardinalis, cardinal flower
Lobelia siphilitica, blue lobelia
Lonicera sempervirens, honeysuckle
Lupine
Lychnis, rose campion
Malva, rose mallow
Manzanita
Maranta, prayer plant
Mentha, mint
Mimosa, invasive tree in certain spots, but good to know it has this quality
Mirabilis jalapa , 4'o'clocks
Monarda, beebalm
Nepeta, catmint
Nicotania silvestris
Nicotiana alata, flowering tobacco
Ocimum basilicum, basil
Pelargonium, annual geraniums
Penstemon, beardstongue
Pentas
Petunia, petunia
Phaseolus coccineus, scarlet runner bean
Phlox
Phygelius, cape figwort
Physostegia, obedient plant
Plectranthus, 'Mona lavender'
Rhododendron, azalea
Salvia, sage
Saponaria, soapwort
Saponaria officinalis, bouncing bet
Scabiosa, pin cushion flower
Sidalcea, prairie mallow
Silene
Streptocarpus saxorum, Streptocarpella
Tropaeolum majus, nasturtium
Tropaeolum peregrinum, canary creeper vine
Verbena
Veronica
Vitex, wild grape
Weigela
Zinnia