These are must have add on's. how can you live without them??
Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
Automatically highlight and count all occurrences of the selected text with just a click (substitute for Ctrl-F with highlight option). Another click in the document removes highlighting.