1. Find out who stopped being your friend
2. View the list of emoticons in the chat
3. What to write in captcha
When promoted for a security check; you only need to type the letters. Everything else can be left out.[Via]
4. Changing the theme
Pagerang will allow you to change the layout of your Facebook page, but this change is only visible to you. This tool is available for Internet Explorer and Firefox.
5. Receive Facebook notifications on messenger