Lightbeam for Firefox - Mozilla is the not-for-profit behind the lightning fast Firefox browser. We put people over profit to give everyone more power online.

Temporary Containers - Firefox Add-on that lets you open automatically managed disposable containers

AllAccounts - AllAccounts is an extension that allows Firefox to connect to websites using different user names.

island - a free and opensource alternative to parellel space

Session Box - Using websites with multiple accounts at the same time is made easy.

Tree Style Tab - Tree Style Tab is an all-in-one Firefox extension that provides ability in order to operate tabs as a tree.