Hillman 3-mm x 0.5 Zinc-plated Steel Hex Nut (20-Count) in the Hex Nuts department at Lowes.com
Everbilt M3-.5 Stainless Steel Metric Hex Nut (2-Piece per Bag) 842318 - The Home Depot
Nut M3 6x10 (100-pack) | Totemmaker.net
M3 x 0.5mm/M3n Nuts – 3d Printer Part
10 Pack - Thin M3 Square Nuts | Partsbuilt 3D
Pololu - Machine Hex Nut: M3 (25-pack)
900PCS M6 M5 M4 M3 Nuts and Bolts Assortment Kit Stainless Steel Metric Assorted Machine Screws Set Phillips Drive Pan Head - China Hex Bolt and Nut, Metric Bolts and Nuts Assortment
Wine Red - M3 M4 M5 M6 Aluminum Alloy Hexagon Full Nuts Hex NUT Female, Anodized | eBay