A new major version of Ksnip screenshot tool was released yesterday with numerous improvements like global hotkeys for taking a screenshot on Linux (X11) and Windows, a system tray icon and the ability to start Ksnip minimized to the tray, the ability to add watermarks to screenshots, and more.
Ksnip is a free and open source Qt5 screenshot tool that runs on Linux (X11, and experimental KDE and GNOME Wayland support), Windows and macOS.