How to list all desktop apps in Linux?

Just search .desktop files in /usr/share directory.

sudo find "/usr/share" -type f -name "*.desktop"

Sources:

• https://manpages.ubuntu.com/manpages/trusty/man1/i3-dmenu-desktop.1.html
• https://stackoverflow.com/questions/5927369/recursively-look-for-files-with-a-specific-extension