A project of the Native Plant Trust, Go Botany allows you to search for wildflowers (and other native plants) through a dichotomous key. Their database is thorough and you’ll learn more than just how to identify them.
The best way to help pollinators is to provide more of the food that they need to survive. Native plants can support hundreds more species of pollinators than non-native ornamentals, so as much as possible, incorporate native plants into your garden and landscaping.
Hummingbird feeders with a sugar-and-water solution can provide supplemental food for hummingbirds and enjoyment for humans. Maintained properly, feeders won’t harm hummingbirds and will give them the energy they need to go after their real desired food: insects.