island - a free and opensource alternative to parellel space

Greenify - Greenify is a mobile app that gives you greater control over your Android device's power usage, allowing you to get a lot more mileage out of your battery life without having to constantly plug it back into a charger.

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

Accubattery - Monitor's battery capacity through the use of science

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.

Power Battery - Power Battery, as the most professional battery saver app, could get up about 60% more battery life for Android phones or tablets.