Scripts I've worked on:

User:The Earwig/copyvios.js
Adds a "Copyvio check" link to the tools sidebar that runs the current page through Earwig's Copyvio Detector
User:The Earwig/permalink.js
Adds a link next to page headers that copies a permalink to the section to the clipboard via Special:Permalink
User:The Earwig/revdel-responder.js (documentation)
For admins, adds buttons to respond to {{Copyvio-revdel}} requests; useful with User:Enterprisey/url-select-revdel

My custom skin pages:

User:The Earwig/common.js
User:The Earwig/common.css

Old scripts retained for historical interest (unmaintained):

User:The Earwig/afc-helper.js
An old predecessor of WP:AFCH, for reviewing redirects. Also includes User:The Earwig/afc-helper1.js and User:The Earwig/afc-helper2.js.
User:The Earwig/orfurrev.js
Modified version of User:Legoktm/rescaled.js for processing Category:Non-free files with orphaned versions more than 7 days old; now handled by bot