Display Manager

GNOME Display Manager (GDM) being displayed on a fedora workspace

An screenshot taken of SDDM

A Display Manager (DM), also known as a login manager, is typically a graphical user interface that is displayed at the end of the boot process in place of the default shell. It often includes a login screen for entering your credentials and the option to choose which desktop environment and Display Server to use. While often graphical, a Display Manager can also run within the TTY itself [referencing ly and cdm here, links needed].