That should get you started :-) If you were focussing your question, we could point you to a smaller list. That is is also by no mean exhaustive, but should have the usual suspects.
Recording / Serverless
- open source - git - www: RecordRTC
MCU/SFU
- open source - git - www: lynckia/licode
- open source - git - www: meetecho (janus)
- open source - git - www: kurento
- open source - git - www: jitsi (meetme)
- open source - src - www meedoze
- open source - git - www: media soup
- open source - git - www: Pion
- acquired by cisco www: acano
- proprietary - docs - www pexip
- proprietary - src - www
openClove (pivoted)
- proprietary - git - www tokbox (openbox)
Signaling
- holla (used by twelephone)
- openPeer (hookflash)
API / SDK
- twilio (audio only)
- requestec (product: saypage)
- plivo
- Tokbox
- QuickBlox
- openClove
- tropo (audio only)
- weemo
- voximplant (audio only?)
- Priologic (easyRTC, tawk.com, proPhone)
- Dialogic
- bistri
- Apidaze
- CafeX
- hookflash
- Apizee (apiRTC)
- &yet (simpleRTC)
- RTCMultiConnection (muazkhan, demo)
- crocodileRTC - the company has been bought/absorbed three times over. I don't know what is the status of this library, you might want to contact peter dunkley for update.
- peerjs (data channel)
- rtc.io
- webrtc.io (no changes for almost a year)
- webrtc-data.io (stripped down, data only version of webrtc.io)
Product
- webrtc-enterprise.com (uses SkywayJS)
- talky.io (uses simpleRTC)
- tawk (uses easyRTC)
- rtccopy (uses webrtc-data.io)
- twelephone
Tutorials
- http://www.html5rocks.com/en/tutorials/webrtc/basics/
- http://www.html5rocks.com/en/tutorials/webrtc/infrastructure/
- http://www.html5rocks.com/en/tutorials/webrtc/datachannels/
- https://developer.mozilla.org/en-US/docs/Web/Guide/API/WebRTC/Peer-to-peer_communications_with_WebRTC
- https://bitbucket.org/webrtc/codelab
