KDE
KDE Plasma
Trinity Desktop Environment
Budgie
GNOME
Cinnamon
MATE
XFCE
LXDE
LXDE
LXQT
Razor-qt
Enlightenment
Moksha Desktop
X.org is founded as a fork of XFree86.
The Wayland project was started.
Gnome 3.0 was released.
KDE 4 was released.