No clue what this is, was just in my soil pile one day. Doesn't look like anything I planted. I think it might be a weed but it hasn't done much in a week or so.
Black medic/black clover...a weed.
I have a lot of bur clover on my property. That looks like bur clover to me, but bur clover and black medic foliage look very similar.
They can both be considered weeds, although both are apparently cultivated by some people for various reasons.