Extension to inject scripts into whatever web page
Must be for older or heavily re-policied chrome, because current security policies won't allow for the scripts to run (they give extensive errors in the console, some in which could be disabled but it appears that some cannot). It might also be a chromium-only thing. I didn't test it there. Regardless of the two, it did not work at all for any of my test cases.
https://textexpander.com/
http://scripty.abhisheksatre.com/
Dorian Rouby
metarmask
Grephy
https://insertlearning.com/
https://ghostinspector.com/
Anbarasan
https://jasper.ai