While standard posts are 1" diameter, there are companies that sell 3/4" round posts. In case you need it, you can get split sleeves for those rare posts here
Screw In Post Inserts For Wire Shelving - 4 Pack
Apollo Hardware 3/4 Inch Shelf Clips/Split Sleeves, Black, 2 Pack/8 Pair (3/4 & 19.1mm Diameter Post Size)
3mm, 5mm, 1/4, 7mm All Shelf Pin Sizes, Flat Spoon Style, Nickel, 100 Pack Kit
Constructed of durable plastic, these clips effortlessly snap together to assemble onto the shelving pole, then can be easily adjusted to your preferred shelf height. Ideally fits Lowes item 328961.
Style Selections Pole Clip - Black - 1.38 x .75 x .75 - 4 ct
Regency Enclosed Base Table Mid-Shelf Clip - 4/Pack
INCREWAY 30 Pack Shelf Support Peg, Clear Plastic Locking Shelf Support Pin Clips, Cabinet Shelf Pins Self-Locking Bracket Clips Fits 1/
20-Lb. Shelf Support Peg, Nickel, 1/4 In., 8-Pk.
1 Diameter Wire Shelf Clips Shelving Split Sleeves Lock Locking Plastic 24 pair
Wire Shelving Shelf Lock Clips For Dia.22m Tube,shelving Split Sleeves Lock Metal Rack Locking Plastic Clips(4 Pairs) - Storage Holders & Racks - AliExpress
Add RAD + Modern floating shelves to any space with our easy-install Aksel HD Heavy-Duty Floating Shelf Bracket. Just add wood!.
Aksel HD Floating Shelf Brackets
HSS Wire Shelf Plastic Lock Clip, Fits 3/4 Pole Diameter Black, 8-Pack, Hardware
The Best Heavy-Duty Shelf Brackets - Essential For Wall Shelves
Product Description These small shelf support pegs are constructed of clear plastic with a 1/8 in. (3 mm) steal stem and a 5/16 in. x 5/16 in. square, flat seat. These pegs are used to support shelving in cabinet units. From the Manufacturer This shelf support peg is constructed from clear plastic. It features a steel peg that adds strength for the shelf support. These pegs are used for support in shelving or cabinet units. FEATURES Vinyl Construction Gray Vinyl 36 in. long 1-7/16 in.
Prime-Line Products - Shelf Support Peg Steel Pin Clear Body, 8/pkg