Lettuce would be your best bet. Carrots will do alright if they get bright indirect light and aren't overshadowed too much. Radishes will get tall enough to reach the light and compete with the pepper foliage.

Here is a link that might be useful: Kim's PA garden

Thanks! What about the chards, chives, scallions, any types of herbs? Any herbs that can stick around through the year would be especially welcome.
Even some flowers could be interesting.

Well, my herb bed is crammed full and does fine that way... so you could probably fit herbs in under your plants and they would be happy.

Besides lettuce, you could try mache, arugula, mizuna, or spinach... I don't know how cold your winters get, but those are pretty hardy and easy to grow. My own personal experience with chard is that it is happiest with more sun, but you can always try it and see what happens!

Lori

Most my peppers were rock mulched, but I had two that were open to some south sun so I planted turnips under them and they both grew fine. they were the purple top. I did harvest them when young, about the size of my thumb. I was surprised at how well they grew as I never companion planted them before, or out of the full sun as far as that goes.One pepper to the square foot, four turnips one in each corner. I don't have a date in my notes, but would guess middle of August for turnip seeding. Thanks.

Curt:-)

So glad to hear I'm not the only one whose eggplants and peppers have decided to stay through the fall. I almost pulled them this summer they were doing so little. Now, I can't keep up with the eggplants and keep giving them to friends.

I love the idea of trying to underplant them with lettuce or spinach as you suggested. It's almost all shade under the plants, but I'll give it a shot. Thanks for the suggestion.