A free and open-source browser extension that filters NSFW content based on keywords.
https://addons.mozilla.org/en-US/firefox/addon/hydrargyrum/
Download and unzip https://github.com/Moogamouth/Hydrargyrum/archive/refs/heads/master.zip.
Go to chrome://extensions/.
At the top right, turn on Developer mode.
Click Load unpacked.
Find and select the extension folder.