Login Designer allows you to customize the login screen for accessing WordPress. What's awesome about it is that it uses the native customizer options. Making customization a breeze, great for client projects or indeed stamping your own design on things.
Cierge is an open source server that handles user signup, login, profiles, management, social logins, and more.
Instead of storing passwords, Cirege uses magic links/codes and external logins to authenticate your users.
Since it is an OpenID Connect server, Cierge works seamlessly with any tech stack.