Clover (trifolium repens) is often considered a weed, however….

Clover attracts pollinators. Bees love clover's white or purple flowers, as do a particular species of wasp, which do not sting but eat aphids. It is anitrogen-fixing plant. It pulls nitrogen from the air and stores it in its roots. As the roots die and decay, the nitrogen enters the soil where it can be used by other plants.