Similar CSS Color Finder
Update: CIEDE2000 support added to the existing CIE94 support.
It would seem that very similar but non-identical colors seem to pop up often in CSS files of any reasonable age, and I became sick of them. This started as a little script to help me find them in a stylesheet, and grew into this full-fledged tool.
This tool will scan CSS and CSS-like files like Sass, Less, etc and find colors similar to each other within a set tolerance.
There is a command line version of this with Continuous Integration support available on GitHub.