SDDM (Simple Desktop Display Manager) is a modern, free and open source Display Manager available on Linux and other Unix platforms like FreeBSD. It works both with X11 and Wayland, and is based on QtQuick, a framework to build QML applications. SDDM allows a great degree of customization and; thanks to this, a lot of custom themes are available for it.
I3 is one of the most used tiling window managers on Linux. A tiling window manager arranges windows in a non-overlapping way: this allows us to use screen space efficiently, but can require a little bit of time to get used to.