This is my go-to screenshot tool for Linux; I've been using it almost daily for years now. It's by no means as feature-rich as ShareX for Windows, but it works

This is my go-to screenshot tool for Linux; I've been using it almost daily for years now. It's by no means as feature-rich as ShareX for Windows, but it works perfectly for what I need. It covers the essentials like simple annotations, blocking out areas of screenshots, saving local copies, etc. I made some tweaks to support my own custom image uploader API, and similar to the comment by geoka9, I have it set up to take a screenshot, upload to my app, and copy the URL into my clipboard all behind a single shortcut.