Allows using any of your logged in devices as second factor
RCDevs OpenOTP Application enables Multi-Factor authentication for your users.
An app for Nextcloud to allow an administrator to direct a user to an external site for changing their password.
Authenticate users against an jasig/apereo CAS Server (https://github.com/apereo/cas)
Allow users logging in using their mailbox credentials as managed via ISPConfig
Allows administrators to restrict logins to their instance to specific IP ranges.