Monarch Butterfly
Food: Meadow Blazingstar is a favorite nectar source for adults, but they will also peruse Joe Pye Weed, Purple Coneflower, etc)
Water:
Cover: nearby forbs, grasses, shrubs, and trees.
Place to Raise Young: Milkweed Plants (larvae are 100% dependent on Milkweed plants - Common, Swamp, Butterfly, or Whorled Milkweed)
Hummingbird
Food: lots and lots if small bugs, especially to feed to young. Adults attracted to the nectar of long tubular flowers, epecially red and orange colored flowers. Cardinal Flower and Colimbine are excellent plant choices. I've also seen them on Morning Glories, which are natibe to Central America (hummingbirds migrate all across North and South America, so they are quite familiar with some of the plants that we grow as "annuals" this far north)
Water: probably derive from nectar, but a waterfall or fountain with lots of spray might be attractive to hummingbirds.
Place to Raise Young: they make a very small nest, from such things as spider webs and pieces of ferns.
Goldfinch
Food: Insects and Seeds
Water: Birdbath, Pond, Fountain, maybe Cup Plants
Cover: large plants, shrubs, and trees. Their summer colors match the colors of Cup Plants exactly, it is fun to watch them harvesting the seeds (do they drink from Cup Plants too? Do they eat the aphids?).
Place to Raise Young:
American Robin
Food: Insects, Berries
Water: Birdbath, Pond
Cover: Trees
Place to Raise Young: almost any "shelf" space will do, including around windows and doors which sometimes creates a conflict for humans. Their nests can also be vulnerable to being blown away by the wind if the shelf space is too open to the elements (I have found shelf boxes to be completely useless). Their eggs are extremely vulnerable to predators and other birds, so they have to pick the most secure location they can find and guard it.
Dragonflies
Food: Insects
Water and Place to Raise Young: Lake, Creek, or Wildlife Pond. Dragonflies spend most of their lives under water, preying on other water bugs. They only emerge with wings to fly above water for a short while, to mate, and continuing their predatory habits (now eating flying insects) before dying.
Cover: Plants and tree branches with places to "perch" are appreciated. Although this probably helps them hunt (other insects need to find cover from Dragonflies!).
Even if you can't provide a pond for Dragonflies, having an insect-rich yard will ensure that you see adult Dragonflies in your yard.
Fireflies
I live 6 blocks from the river, and I usually see one firefly each year! Hopelessly lost I assume, but with our combined efforts, there's no reason we couldn't have more "twinkling" lightning bugs in our summer backyards! There are tons of them nearby at Fort Snelling State Park.
Food: Soft bodied insects, slugs, snails, worms, other larva, even smaller fireflies! Adults may feed on nectar and pollen too.
Water and Place to Raise Young: Fireflies spend around 2 years underground, as larva or "glow worms". They need moist dirt to develop and grow in, full of soft bodied insects to feed on, and of course completely free of pesticides and lawn chemicals. Their final transformation into adult fireflies with wings also takes place in moist soil (i.e. close to a river, creek, lake, or pond).
Cover: the more native plants and "wild" unmowed areas you can provide in your yard, the better. Fireflies sit on long grass during the day, and female fireflies often do not fly or have wings at all, they dwell on the ground and plants. The males fly around at night using their light signals to flirt with the females and to mate. For this reason, it is especially important to turn off lights at night - or compromise with motion sensing lights that shut off when no one is walking by.
The adult fireflies only live for a couple months to mate, and then die.