The Web Authentication Working Group will develop recommendation-track specifications defining an API, as well as signature and attestation formats which provide an asymmetric cryptography-based foundation for authentication of users to Web Applications.

Standard

https://www.w3.org/Webauthn/
https://github.com/w3c/webauthn 
https://www.w3.org/TR/webauthn/

Overview

https://webauthn.guide/
https://passkeys.directory/ - Passkeys.directory is a community-driven index of websites, apps, and services that offer signing in with passkeys.
https://passkeyindex.io/ - Your Resource for Platforms, Apps, and Websites Supporting Passkey Login
https://slides.com/fidoalliance/webauthn-overview

Browser Support

https://webauthn.me/browser-support

Passkeys Authenticator AAGUID Explorer

https://passkeydeveloper.github.io/passkey-authenticator-aaguids/explorer/

Awesome Webauthn

https://github.com/herrjemand/awesome-webauthn 

Demo

https://webauthndemo.appspot.com/
https://webauthn.org/
https://webauthn.me/ & https://webauthn.me/debugger
https://webauthntest.azurewebsites.net/ & [GitHub] 
https://developer.chrome.com/docs/devtools/webauthn/
https://github.com/herrjemand/FIDO2WebAuthnSeries 
https://www.passkeys.io/
https://demo.quado.io/
https://passkeys.dev/

Passkey AAGUIDs

https://passkeydeveloper.github.io/passkey-authenticator-aaguids/explorer/ [GitHub] 

Usage more than Account Security

https://blog.cloudflare.com/cap-expands-support/ - More devices, fewer CAPTCHAs, happier users

Opensource

https://github.com/google/OpenSK  - OpenSK is an open-source security keys written in Rust
https://github.com/solokeys/solo  - Solo: open security key supporting FIDO2 & U2F over USB + NFC
https://github.com/makerdiary/nrf52-u2f  - nRF52 FIDO U2F Security Key
https://github.com/conorpp/u2f-zero  - U2F USB token optimized for physical security, affordability, and style
http://scateu.me/2016/11/30/u2f-zero.html - U2F-Zero制造及使用手记