Wikipedia - Title Search Links - Screen Wiktionary - Word Search Links - Screen IMDb - Add search links to Movie, TV Series, Person, and Character pages - Screen Rotten Tomatoes - Add search links to Movie, TV Show and Person pages - Screen Google - Replace "Videos" tab with link to YouTube - Screen
Also an options dialog to enable disable the script on selected sites.
Version 4 tested and working on:
Firefox + TamperMonkey
Chrome + TamperMonkey