Looking for logging into the Firebase Unity site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Firebase Unity site. After that you can login as usual with your login credentials.
https://firebase.google.com/docs/auth/unity/start
https://firebase.google.com/docs/auth/unity/facebook-login
https://firebase.google.com/docs/auth/unity/start?hl=ko
https://xinyustudio.wordpress.com/2017/01/22/using-firebase-in-unity3d-tutorial-2-authorization-and-user-login-example-with-user-name-and-password/
https://github.com/firebase/quickstart-unity/tree/master/auth/testapp
http://totuworld.github.io/2018/03/22/firebaseandunity-01/
http://totuworld.github.io/2018/03/22/firebaseandunity-02/
https://stackoverflow.com/questions/43731007/unity-firebase-how-to-authenticate-using-google
https://medium.com/teamarimac/how-to-develop-a-complete-leader-board-for-a-unity-game-using-firebase-facebook-sign-in-google-d865f577b303
https://assetstore.unity.com/packages/tools/integration/firebase-authentication-android-ios-82467
https://answers.unity.com/questions/1392251/firebase-authentication-with-facebook.html
https://community.playfab.com/questions/16282/firebase-google-login-and-unity.html
https://www.udemy.com/integrate-firebase-into-unity-with-play-games-services/