#1: Search+ for Google Chrome
Summary: Instantly search Google+ from the omnibar.
Summary: This tab can help you stay on top of tasks that you need to complete on a daily or weekly basis. Set websites to open (and close) at specific times of the day.
Summary: Create a list of all the open tabs. While you can restore a list of URLs you have to come across that list to open all of the tabs at once. I see this more for teachers being able to copy a list of all of the URLs to share with students. Or the students can then copy that list and paste it into the restore to have all of the tabs opened up at once.
#4: Search Preview
Type: Search Tools
Summary: Enhances your search pages by inserting preview images and related links to the sites that appear. This feature is supported in Google, DuckDuckGo, Yahoo and Bing.