Desktop environments are always developed alongside a set of applications, which is what differentiates them from simple desktop shells. These applications aren't exclusive to the desktops they were made for, they're simply designed to fit their aesthetic and design philosophy to offer a more consistent experience. Most desktop environments have a fairly limited set of applications, covering mostly the essentials. The most commonly found types are terminals, file managers, settings, image viewers, media players, text editors, screenshot apps and software centers.

GNOME and KDE are the exceptions, by virtue of being much larger than all other desktops. Both maintain a very extensive set of applications with a wide range of purposes, which tend to be widely used regardless of desktops. GNOME's Evolution and KDE's Kdenlive for instance are among the most popular apps on Linux, since they're among the best apps to use to fulfill their respective purposes (PIM and video editing).