I've built a few tools that I use in my daily work. They're free to use, and I hope they help you out as well.
Password Generator
Generate safe random passwords. Password generation is done client-side (on your computer) using JavaScript.
RAID Space Calculator
A RAID calculator tool to help you determine storage capacity and configurations for different RAID levels including RAID 0, RAID 1, RAID 0+1, and RAID 5