Keyhole Hangers (Mini) Picture Hanging Kit holds up to 100LBS In stud.
Geesatis 50 pcs Keyhole Hangers Heavy Duty Single Hole Hanging Plates Metal Picture Hanger, with Mounting Screws, 43 x 16 mm, Silver, Flat Surface - Amazon.com
Zorveiio 50 Pcs 1” Single Keyhole Hangers Metal Keyhole Hanger with Screws, Keyhole Hanging Plate Hanging Bracket for Mirror Picture Frames Photo - Silver - Amazon.com
Adiyer [20 Pack] 43mm x 16mm Single Keyhole Hangers Hanging Plate Hardware for Mirror Picture Frames - Amazon.com
Keyhole & Picture Hanging Router Bits
30pcs Golden Picture Frame Hanger Hooks Metal Keyhole Fasteners For Mirror Photo Frame Clock Home Decor - Multi-purpose Hooks - AliExpress
Keyhole Hanging Kit takes the pain out of hanging with keyhole slots.