Fliqlo Screensaver - A screensaver that displays the time using a flip clock.
coconutBattery - With coconutBattery you are always aware of your current battery health. It shows you live information about the battery in your Mac and iOS devices (iPhone, iPad)
Clock.saver - A simple clock screensaver based on Braun watches ⌚
Accubattery - Monitor's battery capacity through the use of science
Aerial - A beautiful aerial screensaver for your Mac
GSam Battery Monitor - Monitor your android devices battery usage.