Website Carbon Calculator - Find out the how much CO2 your website emits
CleanMyMac X - Clean, protect and speed up your Mac
Wren - Offset your carbon footprint by saving rainforests
Fossils - Find and clean out all your old unused files
Klima - Go carbon neutral
DaisyDisk - DaisyDisk is a disk analyzer tool for OS X that visualizes hard disk usage and allows to free up hard disk space.