Which stopper should I get for trophies, cabinet knobs, faucet handles, gear shifts, etc.?

If you are not sure of the screw size, take the item to any hardware store, they have boards with all screw size holes so you can see the size you need. The cabinet knobs are either 10-24 or 8-32. The average trophy is 1/4-20 and antique door knobs are either 3/8-18 or 3/8-20. A lot of door knobs work with the 60-00-01 (301). It is also easy to tap the door knob with a 3/8-16 tap.