CleanMyMac X - Clean, protect and speed up your Mac
Spybot Identity Monitor - Get an overview where your account was leaked.
Fossils - Find and clean out all your old unused files
Snusbase - The industry leading database lookup.
DaisyDisk - DaisyDisk is a disk analyzer tool for OS X that visualizes hard disk usage and allows to free up hard disk space.
LeakCheck - Data breach search engine, low price starting from $10/mo, one email address for free, unlimited API, 7B+ entries