Carpet of sprouts

My day laborer built a planter box to protect the acorn squash and green bean sprouts who are rising above the carpet of tomato seedlings. I saved a few for a friend, but pulled almost all the others. There are a few volunteer seedlings I can't identify so left to grow bigger (really hoping they are cucumbers, but I doubt I'm that lucky). Of the few new seeds, the golden beets with yellow stems are the most striking and can't be confused with weeds or volunteers.