Using "Morning Coffee" extension is the best solution for Firefox. You can add URLs to be opened daily, on specific days or combination of days of the week. Installing the extension gives you a Coffee Mug icon next to the address bar to add, remove or open sites.
   morning coffee firefox 
   The next trick uses the home page button. First, open all the web sites you want to open together in separate tabs. Once they are all loaded, from the Firefox menu bar go to "Tools->Options" ("Edit->Preferences" in Linux).
   Go to the "General" tab and click on "Use Current Pages" button. This will add all the currently open tabs in the list of home pages. Firefox provides a home page button which you can see on the right side of location/address bar (Windows/Linux buttons as below).
   Next time you want to open all your pages, just click on this button.
   The third trick is to create a folder for bookmarks and bookmark all the sites you want to open together under that folder. This can be done from "Bookmarks->Bookmark this page" menu option. Now to open all pages together, go to "Bookmarks->[folder_name]->Open all in tabs".
   You can also click with your scroll button on the folder from "Bookmarks" menu and open all bookmarks stored under that folder in tabs.

Firefox is one of the leading web browsers in the world. There are three tricks that can be used to launch multiple web sites with a single click in Firefox. Let's see the best one first. Using "Morning Coffee" extension is the best solution for Firefox. You can add URLs to be opened daily, on specific days or combination of days of the week. Installing the extension gives you a Coffee Mug icon next to the address bar to add, remove or open sites. morning coffee firefox The next trick uses the home page button. First, open all the web sites you want to open together in separate tabs. Once they are all loaded, from the Firefox menu bar go to "Tools->Options" ("Edit->Preferences" in Linux). Go to the "General" tab and click on "Use Current Pages" button. This will add all the currently open tabs in the list of home pages. Firefox provides a home page button which you can see on the right side of location/address bar (Windows/Linux buttons as below). Next time you want to open all your pages, just click on this button. The third trick is to create a folder for bookmarks and bookmark all the sites you want to open together under that folder. This can be done from "Bookmarks->Bookmark this page" menu option. Now to open all pages together, go to "Bookmarks->[folder_name]->Open all in tabs". You can also click with your scroll button on the folder from "Bookmarks" menu and open all bookmarks stored under that folder in tabs.