Hi Jenn -- this is a happy problem. You are, as they used to say in the comic strip Pogo, "confronted by insurmountable opportunities."
Off the top of my head, other possibilities:
Nepeta? Dwarf lavender? Tradescantia/Setcreasea "Purple Heart"? Felicias, especially the variegated ones?
Dwarf agapanthus -- there's a new one called Baby Pete that's a gorgeous blue and really petite.
Also thyme -- the kind you cook with, but it's a great edging plant as well, campanula poscharskyana (spelling approximate/my apologies to Mr. P.).
Gazanias, especially white ones. I've had luck with arctotis as well (love Arctotis Peachy Mango).
Any of the ice plants, I suppose, but you'd probably have to see them in bloom first. A whole lot of them are so bright they'll put your eye out.

Hope this helps,
Kay

Purple heart in the ground here is like a weed...invasive.

Santa Barbara Daisy, gazanias, lamb's ears, or more Rozanne.
I also love the little bitty leafed ice plants. They look almost mossy.

Thank you for the suggestions.

We have a few small Agapanthus there now. Scented pelargoniums would also work -- they come in many shapes, sizes and colors and many grow into a billowy mound with trailing stems. We have a self-sown Apple-scented one that popped up at the corner of a path at the edge of the patio -- exactly where I might have planted one!