Google Chrome Dev Tools

http://www.siteparticles.com/efficient-workflow-using-sass-locally-and-realtime-ftp-update-all-in-one-save

http://remysharp.com/2012/12/21/my-workflow-never-having-to-leave-devtools/

CodeKit https://incident57.com/codekit/

MixTure http://mixture.io/

PreprosApp http://alphapixels.com/prepros/