Everbilt 9/16 in. x 3 in. 2-Hole Zinc-Plated Keyhole Fasteners 811128 - The Home Depot
Hillman 5lb Keyhole Hangers in the Picture Hangers department at Lowes.com
Moses Keyhole Hangers
Steel Single Hole Keyhole Hangers - 2 Pk by Hillman at Fleet Farm
Black Steel Keyhole Hanger | 316L Steel Gauges – ThePlugCrate
20 Pcs Keyhole Hangers Metal Fasteners for Picture Frames Mirrors Cabinet,Metal Keyhole Hanger Hanging Fasteners Hardware Flush Wall with Keyhole, 42 mm x 14 mm Flush Mount Hardware(No Screws,Silver) - Amazon.com
Keyhole Hangers (Mini) Picture Hanging Kit holds up to 100LBS In stud.