The Xfce4-screenshooter is an application that can be used to take snapshots of your desktop screen.
Gnome screenshot
GNOME Screenshot is a small utility that takes a screenshot of the whole
desktop; the currently focused window; or an area of the screen.
Ksnip
KSNIP est QT secundum crucem-platform screenshot tool quod providet multis annotation features in vestri eenshotsscray.
Flameshot
Flameshot