I have always wanted to try "Gay Butterflies".
I have grown "Hello Yellow", but the wild orange is much hardier

@Leafhead In Wisconsin that must be, of course, very important. Hardiness here is only an issue for actual tropical plants. Lantana even, grown elsewhere as an annual, is happily perennial here.

@MikeInBatonRouge
I used to grow tons of it in Florida. Oddly enough, most cultivars are not that effective . I stayed with the good old orange and yellow or pink and yellow varieties. I also grew it's close relative, Porterweed. Another EXCELLENT nectar plant.
I don't use Lantana here as it is not nearly as effective.
For nectar I rely heavily on weeds like Dandelions, Pussy Willow and violets early, to Veronica, Salvia, Joe-Pye Weed, Liatris, Milkweed and Phlox.
I grow a lot of host as well, including Nettles, Everlasting, Pussytoes, Golden Alexandar, Black Cherry, Hackberry and of course Milkweed.
Milkweed, as well as being the sole host for Monarchs, is also a fantastic nectar source

@Leafhead great list. I miss pussy willows, lol. It was great back in Olympia, WA, when I was a little kid. A plant with "fur." I see none here in the deep south.
Swamp milkweed, Butterfly (milk)weed, purple coneflower, and Stokes Aster are my core perennials for my "plan," but I want variety. Joe Pye Weed I have only recently learned of; not sure if I have seen it. Common Milkweed reportedly doesn't do well here.

I want variety, but plenty of annuals for nectar, for bees and hummingbirds, too, not just butterflies. Also native coral honeysuckle, a couple of large flower clematis, and mixed wildflower seeds I scattered through both my main rose beds. I have planted a lot of perennial blue salvia, marigolds, zinnias, cosmos, and dill, morning glories and moonflowers in their own separate bed around a multi-trunk stump, and because our growing season is so long, I am eying cool season crops of carrots, broccoli, and peas, as well as violas and columbines, etc.

Sort of amusingly, I have allowed my lawn weeds to grow and bloom for pollinators, and so I keep having people knock on my door to ask if I need my lawn mowed. I eventually hope to crowd out most of my lawn.