I was inspired by HunterGreen's pliers holder. I have dozens of them in my shop, but they tend to rotate up and fall off the pegboard when I grab the tool they are holding. The locking clip prevents this. The clip is designed to require a LOT of force to insert; the screw driver slot allows you to pry it out to remove the holder from the pegboard.

Ultimaker

Ultimaker 2

No

Yes

100%

Print locking clip with a strong, smooth material like polycarbonate or ASA.
Print the loops with nylon or glass-fiber-reinforced nylon (e.g., FiberForce Nylforce GT).
Print the spring clips with a material that won't break when flexed, e.g., glass- or carbon-fiber-filled nylon or PETG.