Unity - Voice Chat
UniVoice
https://github.com/adrenak/UniVoice
AirPeer
https://github.com/adrenak/airpeer
Run Voice Chat in your Unity game
https://medium.com/agora-io/add-voice-chat-to-your-unity-game-2194dbcf6eff
Voice & Text Chat in Unity
https://www.youtube.com/watch?v=XCqi0B1zqko
Adding Voice Chat to a Multiplayer Cross-Platform Unity game
https://www.agora.io/en/adding-voice-chat-to-a-multiplayer-cross-platform-unity-game/
Vivox
https://unity.com/products/vivox
https://assetstore.unity.com/packages/tools/audio/vivox-voice-and-text-chat-148188
Agora.io:
https://www.agora.io/en/solutions/gaming/
https://assetstore.unity.com/packages/tools/video/agora-video-sdk-for-unity-134502
PUN
https://www.youtube.com/watch?v=r2HqBQ44x40
Multiplayer Unity Using WebRTC
WebRTC in 100 Seconds // Build a Video Chat app from Scratch
Using Web Solution