1. Boost for Facebook
Download Boost for Facebook can do autopoke, all rollover profile picture thumbnail and the video can also be downloaded at facebook.
Download: https://addons.mozilla.org/en-US/firefox/addon/3120

2. Adblock
To hide the ads on Facebook.
Download: https://addons.mozilla.org/en-US/firefox/addon/1865

3. Facebook Video
With the help of facebook video addons you can download a video on facebook to share even did convert the video.
Download: https://addons.mozilla.org/en-US/firefox/addon/9614

4. Friendbar
Friendbar is actually a toolbar that allows you to send updates and comments
Download: https://addons.mozilla.org/en-US/firefox/addon/10223

5. Facemood
Collection of emoticons, emoticons that you can use the facebook chat.
Download: https://addons.mozilla.org/en-US/firefox/addon/52179

6. Firestatus
So that always seem to exist on Facebook you can use Firestatus. Firestatus can update your status without opening the site, the message would be updated can also be timed, eg, updated every seven minutes once, and so on.
Download: https://addons.mozilla.org/en-US/firefox/addon/firestatus/

7. Better Facebook
Make your Facebook better. With these add-ons you can Tabbed news feeds, feed advanced filters, hide read posts, highlights new comments, static header bar, enhanced navigation, friend tracker, expand the similar posts, custom CSS, and more.
Download: https://addons.mozilla.org/en-US/firefox/addon/better-facebook/

8. PhotoZoom Facebook
When the mouse over a thumbnail, a tooltip will appear with the bigger picture in it.
Download: https://addons.mozilla.org/en-US/firefox/addon/facebook-photozoom/