How can I add a Stack Exchange login to my preexisting account?
3652
How do I change my login provider(s)?
90790
stackoverflow.com without OpenID
98146
Login to Stack Exchange account doesn't use HTTPS/SSL?
71471
Why separate Stack Exchange accounts?
73379
How can I link two Google accounts to one Stack Exchange account?
80208
Why doesn't Data Explorer log in with Stack Overflow login?
64326
Add a link to Stack Exchange portal in the Top Bar
31381
How do I find out the user name and password for an existing account?
41394
Logins can be added/removed without reauthenticating, allowing temporary XSS to be escalated to permanent account hijacking
109162
Defaulting to the sign-up form?
143137
Unable to login to Stack Exchange iOS application
156501
How do I really change my login email address?
32925
What steps to add a user to a system without using useradd/adduser?
25495
Can't log in to the Stack Exchange app with a Google account
94746
Switch from OpenID to a Stack Exchange login
83503
How to add existing user to an existing group?
156982
How to restore/add previous user account