Some registries:

• The Nation Registry of Experts
• American Bone Marrow Donor Registry
• Malinois Registry of Merit
• US National Do-Not-Call Registry
• Gift Registry
• A Directory of Affiliate Programs
• Domain Name Registry for Organizations
• Georgia Registry of Interpreters for the Deaf, Inc
• Oilfield Workers Registry
• Clown Face Registry
• National Film Registry
• Mushroom Poisoning Case Registry
• Speedtrap registry
• Object Identifier Registry
• Organized Crime Registry
• International Registry of Artists and Artwork
• Worldwide Registry of Professional Electrologists
• The National Haunted Places Registry

Apparently there is no place where I can register that my body parts are large enough, thank you.

Registries try to solve a coordination problem, a search problem, a certification problem. But they only work well when they achieve sufficent scale to capture the network effects that make them valuable to their users. A successful registry becomes a standard; the standard way to answer a some class of questions. EBay has managed to do that for junk.

Registry design gets a lot more interesting when you want to control who’s
allowed to know what when. It gets more interesting when you start trying to standardize broadly what questions people can ask.