Although the plant looks like it might belong in the mint family (a very large plant family with many species), we can't be certain from the photo which species it is. Plant identification relies heavily on flower traits, especially since unrelated plants sometimes have nearly-identical leaves, and leaf size/shape/color sometimes changes over a plant's life cycle. If you want to keep the plant until it blooms (if there are others that weren't pulled up), we'll gladly take another look if you can send pictures of the flowers. It might not flower this year, though, if it's a young perennial. Otherwise, it might be safer to just remove it if you think it's a weed. From the photos provided, we're unfortunately not able to ID it at this point.

Miri