The other day I noticed that almost every yard between here and town has yellow lantana around their mailbox, if not in beds in the yard. Another frequently planted bloomer is Knockout Rose. One house has more than a dozen.

Some of the things that are perennial for me may act like annuals for you: Pentas, Mexican Bush Sage, Pineapple Sage, Persian Shield.

Nell

No one could want for a longer-blooming, more drought-tolerant and butterfly-friendly plant than Lantana. Not all varieties are perennial but 'Miss Huff' will do.

I really like passionflower vine for its long period of delightful blooms as well.

Part sun-wise, "Endless Summer" hydrangea will keep putting it out. I've planted some Encore azaleas but they're not nearly as showy. There are hardy begonias that bloom happily for awhile, and even those little wax begonias often come back. Perennial salvias (sage) like mentioned above are good hearty bloomers for me.

I've found that there's a great deal of joy in perennial gardening using relatively short-blooming plants, though. It makes walking through my garden exciting (yay my pineapply lilies are blooming! Look, a rain lily!) Whereas my loyal Miss Huff, she is steadfast and true and blooms from summer til frost, but to be honest she gets to be a bit of a bore.

Interesting thought about length of bloom, jennifratrix. So let me amend the original wish to perennials that bloom during summer and fall. That way I can get ideas to mix it up.
I did add a chocolate eupatorium, a couple of white swan coneflowers, and a St. John's wort today. I also put out a shallow pot with some succulents - so I wouldn't have to amend soil for them. Also a hibiscus for a wet spot in the bed. Not sure I'm going to like it though.
Keep those thoughts coming. I'm starting to need recommendations for good filler plants now. The ones you tuck in here and there.

Athens Rose Lantana, Indigo Spires Salvia, any knockout rose, Walker's Low catmint (you'll need to prune it after it finishes blooming for it to bloom again), Ginger Lily (which smells wonderful, but needs lots of water), Salvia Guarantica (you'll need to prune it after it finishes blooming for it to bloom again, also this is a plant much beloved by hummingbirds), Nicky Phlox is a repeat bloomer, Four O'Clocks (you'll need to prune it after it finishes blooming for it to bloom again), and Phyllis Fancy salvia which blooms late summer through frost (it's a huge plant). Coneflowers are an excellent choice. Some periennials I love for thier foilage color are Purple Emperor Sedum, Purple Setcreasea pallida (Purple Heart Wandering Jew), Powis Castle Artemisa, Heuchera (Coral Bell) & Lambs Ear. Some annuals that I've had that have consistently reseeded or come back the following year (barring a very cold winter): begonias, zinnias & cleome.

Have fun!