Changed hardcoded list of DE/WM's to the list that will list DE/WM's that are available in pkg-files folder, so you could just add new WM to the list of options by adding new .txt file and populating list of apps you want (bspwm.txt, i3.txt...)

scripts/startup.sh

@@ -281,7 +281,7 @@ aurhelper () {
 desktopenv () {
   # Let the user choose Desktop Enviroment from predefined list
   echo -ne "Please select your desired Desktop Enviroment:\n"
-  options=(gnome kde cinnamon xfce mate budgie lxde deepin openbox server)
+  options=( `for f in pkg-files/*.txt; do echo "$f" | sed -r "s/.+\/(.+)\..+/\1/"; done` )
   select_option $? 4 "${options[@]}"
   desktop_env=${options[$?]}
   set_option DESKTOP_ENV $desktop_env