XInstaller

Enable/disable:
- Signatures checking (globally or only during installations)
- Signatures checking for F-Droid
- Apps downgrading
- Apps verifying
- Unknown app installing
- Installing apps on external storage
- Forward lock flag
- Keep apps data after uninstalling
- Disabling system apps (+ you can turn off notifications for them!)
- Uninstalling device admins
- Auto installing
- Auto uninstalling
- Auto closing after uninstalling
- Auto closing after installing
- Auto launching (apps) after installing
- Permissions checking
- Apps backuping when installing (to /sdcard/XInstaller)
- JAR verifying
- Signatures verifying
- Installing unsigned apps
- Auto backing up (related to adb backup feature)
- Making any app debuggable
- Showing package names in App info (bonus: click on app version to copy package name)
- Showing version info in App info
- Deleting APK files after installing
- Moving unmovable apps
- Checking SDK version
- Installing in background
- Uninstalling in background
- Launching apps (click on app icon in App info to launch app)
- Opening apps in Google Play (long press app icon in App info to open app in Google Play)
- Exporting apps (click on app name in App info to export APK file to XInstaller folder; bonus: long press app name in App info to copy app name)
- Auto enabling clear buttons in App info
- Uninstalling system apps (long press Disable button in App info to uninstall (delete) system app)
- Backing up all (even unbackupable) apps
- Changing device properties
- Hiding app crashes
- Confirm signatures check

and maybe more!