Will this bracket work as a standalone repair, or do I need the right side too?

This is the left bracket only. For full bumper support integrity, pair it with the matching right-side bracket. You can install one side if that's the damaged component, but both brackets together provide balanced structural support.

What fasteners do I need to bolt this on?

Mounting method and hardware specs aren't listed here — pull your service manual or the OEM parts diagram to confirm bolt size, thread count, and torque specs for your vehicle. Bring that info when you order fasteners.

Does this come primed or ready to paint?

The bracket ships unpainted hard panel finish. Clean, degrease, and prime before final paint if color-matching is required. Some shops leave brackets bare if they're hidden behind the bumper cover.