I've successfully grown dwarf tomatoes in 5-gallon containers, peppers in 3 and 5-gallon containers, and lettuce, basil, chives, parsley and pak choi in smaller containers. Had mixed success with cucumbers. Squash might be iffy because the vines spread all over. I've never tried to trellis squash vines, but that might be one way to handle it in a large container. The picture shows Gypsy peppers in pots.
