I'm moving these here, from the project page where I originally listed them. Feel free to edit this to add any you find.
- No endorsement of a particular extension is implied.
Browser extensions/addons that show mouseover popups within Wikipedia
- Chrome
- wikipedia plus
- wikipedia quick hints
- wikipedia smart links
- wikipreview
- wikitweaks
- wiki it
- hoverpedia
- LiveWiki (github)
- wikipedia peek
- wikipeeks for wikipedia
- wikipedia hover
- wikihighlight
- wiki on speed
- wikizoom
- wikipopups
- qwikipedia
- wikitopichover
- easywiki
- Firefox
Browser extensions/addons that show Wikipedia/Wiktionary content at any external site
- Chrome
- Firefox