The Xfce4-screenshooter is an application that can be used to take snapshots of your desktop screen.
Gnome-screenshot
GNOME Screenshot is een klein hulpprogramma dat een screenshot van het geheel maakt
desktop; the currently focused window; or an area of the screen.
KSnip
Ksnip is a Qt based cross-platform screenshot tool that provides many annotation features for your screenshots.
Vlamschot
Powerful yet simple to use screenshot software.