List of beneficial weeds

This is a list of undomesticated or feral plants, generally considered weeds, yet having some positive effects or uses, often being ideal as companion plants in gardens.
Beneficial weeds can accomplish a number of roles in the garden or yard, including fertilizing the soil, increasing moisture, acting as shelter or living mulch, repelling pests, attracting beneficial insects, or serving as food or other resources for human beings.
Categories of beneficial weeds.
Trap crops.
Trap crops draw potential pests away from the actual crop intended for cultivation.