LOVIMAG Strong Magnetic Hooks, 12 Pack Magnetic Hooks Heavy Duty 70LBS Strong Neodymium Magnets with Carabiner Hook, Magnet Hooks with Swivel for Kitchen, Hanging, Cruise, Grill, Refrigerator - Black

I hang the collars on the weight horns with the plates. Seems logical since you don't use the collars unless you are loading plates on something. And I hang my cable accessories from the crossmember on the back of the rack using a combination of short pins with carabiners or magnets attached to carabiners .