The Open Source Hardware Association (OSHWA) runs a free program that allows creators to certify that their hardware complies with the community definition of open source hardware. Whenever you see the certification logo, you know that the certified hardware meets this standard.
The certification site includes a full list of all of the certified open source hardware. Here is all of the hardware that was certified in August:
SOMU, a tiny FIDO2 security key from SOLOKEYS.
Lulzbot’s HE Tool Head, a 3D printer head made from hardened steel.
The Escornabot CPU, an open source robotics board from Spain designed to work with an Arduino Nano.
The Escornabot Cervus, an Arduino-compatible controller board for the Escornobot platform.
A USB Morse Keyer, and automatic morse code keyer with USB and Morse key interfaces from Sri Lanka.