1)   pdf-DocPro 5.x
Set presentation properties to PDF files, compress PDFs up to 90 % or create downward compatibility between Adobe FormDesigner, Adobe 7, 6 and 5 !

 2)   Ezilon Toolbar 2.4
Some of the standard features include: a pop up blocker, ability to search the world using Ezilon,major search engines search, Alexa Ranking and Google PR check, Wayback machine (to find how the website looks way back), ability to check images.