Loginways - The best way for manage multiple accounts. Fingerprint protect.
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.
Incogniton - Incogniton is the tool for anyone who wants to say anonymous online. Using websites with multiple accounts at the same time is made easy. It protects users from being detected via (unauthorized) browser fingerprinting. 100% privacy and anonymity.
island - a free and opensource alternative to parellel space
GoLogin - Easily switch between browser profiles to manage user accounts on websites without blocks, suspensions and verifications.
App Cloner - Clone your Android apps so you can use multiple logins.