I just put one of these on my GS500. It is looks good on the naked version, is DOT legal, and has the same bulb socket (h4) as my 2006 GS500F
Emgo Honda Style 6 1/4in. Headlight Assembly - Black 66-64313 https://www.amazon.com/dp/B0068C0QJY/ref=cm_sw_r_apan_i_XB1VVWBXA8PYFWRNXGDX
You'll also need 2x bolts for it. 10mmx1.25mm 25mm long. You can get them at most hardware stores.
If your bike doesn't have a round headlight already, you'll also need fork clamps: OSAN Universal 35mm-43mm Headlight Mount Brackets Fork Ear Motorcycle Chopper Cafe Racer Black https://www.amazon.com/dp/B0171DQ9XA/ref=cm_sw_r_apan_i_8H1NERX1JMR4MGQQNP0J