Edge Launcher gives you fast access to your favorite apps, contacts, and settings with just one hand.
★ Give you quick access to favorite apps, tools, websites, and contacts.
★ Add up to 6 panel
★ Swipe up/down to switch panels
★ Customizable theme, icon pack
For Marshmallow and newer, To prevent the app stopped by itself:
System Settings > Battery > Battery Optimization > Add apps > Edge Launcher > Checked Don’t optimize
Requirements: Android 5.0+
Get on Google Play