CleanMem - CleanMem keeps memory use in check on the system without the memory being pushed to the page file.
CleanMyMac X - Clean, protect and speed up your Mac
Wise Memory Optimizer - Wise Memory Optimizer a simple and effective RAM booster to help you free up memory and get your computer running smoothly again.
Fossils - Find and clean out all your old unused files
Mem Reduct - Mem Reduct is a small application that allows you to monitor and clean your computers memory.
DaisyDisk - DaisyDisk is a disk analyzer tool for OS X that visualizes hard disk usage and allows to free up hard disk space.