Greasemonkey
Used by 4 peopleaddons.mozilla.org ↗
“I use Greasemonkey to automate my web experience (example 1, example 2) in the same way that I use shell scripts to automate my console experience.”
Matt Might Interview, CS Professor (University of Utah) · via Uses This 
“I am probably best-known for having created Greasemonkey.”
Aaron Boodman Interview, Developer (Greasemonkey, Google Chrome) · via Uses This
