as others have mentioned, a window manager is one component of a desktop environment – under ideal conditions, a desktop environment collects and integrates a whole set of packages (both primary and supporting), unifying functional aspects as well as look-and-feel – whereas people starting with a window manager add in tools where working for them takes priority over working with other tools
minimizing your desktop environment
Gnome and KDE
Xfce
LXDE and LXQt
tiling extensions to existing desktops
Pop Shell, Tiling Shell, PaperWM for Gnome
(I know KDE has an equivalent, don’t know what it’s called)
can get simple half- and quarter-tiling in Xfce just through hotkeys
switching out window managers in existing desktop environments
LXDE typically used Openbox
LXQt is pretty much window manager agnostic – distros commonly add Openbox, KWin or Xfwm – Tsujan seems favorable towards LabWC
Regolith packages a Gnome desktop with either i3 (Xorg) or Sway (Wayland) as the window manager
starting with a window manager
can either start straight from tty or rely on a desktop manager
supporting apps usually handled by whatever autostart feature the window manager provides
stacking/floating – most traditional choice is often Openbox (Xorg) but looks like LabWC (Wayland) is continuing its legacy
tiling
tiling window managers tend to rely a LOT more on keyboard hotkeys and less on mouse usage
Xorg – HUGE selection, all down to how much work you want to put in and how large a community there is to help you out
Wayland – currently at the top are Sway (continuing i3’s tradition) and River (trying to grab the Awesome fans)
getting a window manager up and running is only one part of the equation
obvious next steps include choosing a file manager, an image viewer, a document reader, a video player, a web browser
less obvious is the behind-the-scenes apps – seat management, policy kit, clipboard handling, notifications, app launchers, desktop manager