These tiny, beautiful flies are very good to have around. Why?
This is a Long-legged Fly (Dolichopodidae). They are common, but small, so they are easily missed. Most are green and/or bronze colored, and they are quite beautiful. They are also voracious predators, eating all sorts of garden pests, including mites, thrips, and aphids. Their larvae live in the soil, and are also predatory, eating pests in the soil around the plants.