Firefox Multi-account Containers - Sign in to two different accounts on the same site

island - a free and opensource alternative to parellel space

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

App Cloner - Clone your Android apps so you can use multiple logins.

Parallel Space - Parallel Space – Multiple accounts and Two-Face is free to use mobile app that helps you clone or run multiple accounts of the same app simultaneously, and use themes to style your unique space.

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.