Sweet peas might make it, although its a bit late in the season; string beans are a reasonable option - my first row usually goes in on Mother's Day.

You should still be good with radishes, beets, maybe carrots and you might be able to get some leaf lettuce or spinach to use as young greens before they bolt in the heat of summer. Adams still had seed potatoes last weekend and you could try some early / mid season varieties. For herbs, catnip, chives for a fall crop and maybe take a chance on chamomile.

You could plant almost anything that's not eggplant, peppers, squash or such like, the hot weather plants. I have planted tomatoes this early in the past, under glass jugs, and it snowed on them (May 7, Mother's day that year)
they were fine, just the effort did not produce tomatoes much earlier. Memorial day is the traditional planting date for these, I still cover eggplant and squash with remay for a couple of weeks for added warmth and bug protection.

All herbs with the exception of basil would be fine now. Parsley, cilantro, sorrel, loveage, (my chervil lived through this past winter) all onions.

I can't think of any green things that would have trouble now, lettuces, kales, peas and sweet peas went in a couple of weeks ago, arrugula is well up.

They say corn can be planted when the oak leaves are the size of a mouse ear. I've always loved that image.

I just noticed that a lot of self seeded sunflowers are already growing in my garden. Morning glories, too! So when I see that, I figure that those little plants know what they're doing and you're probably safe for the season on most of the tender plants.

I usually plant my tomatoes by mid May and I've never (knock wood) had them killed off, yet.

We had a frost a couple of nights ago but it is still a good time to plant carrots, beets, turnips, lettuce, swiss chard, parsley, endive. Peas were planted two weeks ago and are up. It's still a bit early for beans, tomatoes, squash, cucumbers here - they like warm soil and warm nights. But it's OK to plant potatoes (getting a bit late), onion sets and seed, leeks.

Also consider seeding parsnips, parsley root, cilantro, fenugreek (for greens). In a couple of weeks set out celery and celeriac plants.