Smart garden plans should account primarily for foliage instead of flowers since the majority of perennials only bloom for a few weeks and it's the foliage you look at the rest of the year. To say that foliage is only for shade is to hint that you have no faith in finding flowers for the shade garden, IMO. Plan your garden before you put anything in - layout your planting arrangement on paper accounting for the full grown size of the plants. Don't buy anything until after you've taken your notebook and toured your local gardens - botanical if you have any, neighbors, garden society tours, local high-end nurseries, etc. Decide what you LOVE, make a note of its characteristics and draw it into your plan. Then start small and be patient. To me, the smaller plants suffer less transplant shock and are therefore more likely to survive the move into your garden. There is a world of possibility which only your personal preference can begin to narrow down. Find an inspiration, develop a vision as to the purpose/use may be for this garden and plan plan plan so you don't have to dig up and move around (like I do - LOL). Variety is the spice of life and for some of us the look of a carnival upon which a rainbow just threw up is exciting, to others it's disconcerting and only you can decide where the line is drawn.

One color that's easy to find sun foliage plants for is silver. Lots and lots of choices there. I have 'Silver Mound' artemisa, which is true silver and very feathery looking. It's so filmy it looks like it belongs underwater, but I think it's beautiful. It's also very strong - drought resistant (though I doubt that's an issue this year, it will be again) and loves full sun. One of mine got eaten all the way down to the ground by some danged squirrel, and it's back.

Stachys (lamb's ear) also is pretty attractive, and as fun to touch as it is to look at. It's silver-fur-over-green, or mine is, anyway. I have a dwarf variety that doesn't flower.

I like both of these more than Dusty Miller, but that's an option too, along with variegated grasses and assorted colorful shrubs and shrublets.

The easiest way is to just look at pictures and find out what you like.

You didnt say the size of this new bed, but I will still vote for peony and iris for great long lived and interesting foliage. coarse leaves
like coneflower or perennial salvia look interesting next to delicate foliage from coreopsis.
Silver and blue leaves from lavender and artesmia do great in dry and rocky soil with full sun.
And last but not least, the many beautiful forms, colors, and sizes of sedum.