Ubiquitous: adj., Found and/or used everywhere; constantly encountered; widespread. Usage: "The simple, inexpensive bike hook is ubiquitous in its applications for hanging items from Rhino Shelf DIY Garage Storage Kits."
You won't be able to live without them. Plus they're cheap!
Available at any big-box or hardware store and online for less than a dollar. You screw them directly into the 2x4s of your new Rhino Shelves and hang the most amazing array of "stuff."
Bikes, golf bags, baskets, containers, mesh bags, fishing rods, kayaks, yard equipment, ladders, etc., ad infinitum.
They're easy to install: Get the ones with the screw-in portion being 1/4-inch diameter, by 3/4 to 1and1/4 inches long. The vinyl-coated "hook" portions are commonly 3 to 4 and 1/2 inches long. For 1/4-inch diameter hooks, pre-drill with a 3/16th inch drill bit. Screw them in by hand.
These are available at Home Depot, Lowes, Amazon, Ebay, or your local hardware store. If you're online, search for "bike hook" or "screw in hook."