scrab
Screen grab adds a configurable hotkey to quickly select a screen region and add it as an image source to the current scene
The plugin saves all screenshots into your home directory by default. If you wish to change that, open your obs-studio config and edit it:
Windows:
Open %appdata%\obs-studio\global.ini
Linux:
Open ~/.config/obs-studio/global.ini
Then add the following at the end of the file and replace {path}
with whatever folder you want scrab to use for screenshots:
[scrab]
image_folder={path}
Demonstration
Credits
Screenshot sourcecode reused and slightly tweaked from qTox licensed under the GPL v3.0: