FYTE /Fast YouTube Embedded/ PlayerJS
Hugely improves load speed of pages with lots of embedded Youtube videos by instantly showing clickable and immediately accessible placeholders, then the thumbnails are loaded in background. Optionally a fast simple HTML5 direct playback (720p max) can be selected if available for the video.
Open links in current tabJS
Open links in current tab regardless of _target or site's preferences. Ctrl-click: background tab, Ctrl-Shift-click: foreground tab, Shift-click: new window, Alt-click: force open in current tab
Table of Contents EverywhereJS
On pages which do not have a Table of Contents, but should do, create one! (I actually use this as a bookmarklet, so I can load it onto the current page only when I want it.)