HTTrack - HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.
Workona - A better way to work in the browser.
GNU Wget - GNU Wget is a free software package for retrieving files using HTTP(S) and FTP, the most...
OneTab - Whenever you find yourself with too many tabs, click the OneTab icon to convert all of your tabs into a list. When you need to access the tabs again, you can either restore them individually or all at once.
WebCopy - Cyotek WebCopy is a free tool for copying full or partial websites locally onto your harddisk for offline viewing.
Session Buddy - Manage Your Browser Sessions