##CSS Tools##
Pleeease is a CSS post-processor. The main goal of this tool is to perform all treatments that a pre-processor shouldn't have to do! (eg, dealing with prefixes, convert rem to px, support older browsers, etc.).
Stress CSS JavaScript bookmarklet to test each CSS class on a page and report which are hindering performance.
##Email Design## PutsMail It's a mail test tool to test your HTML mails before sending them.
##Icons## Licon is a simple, useful and lightness pack—icon that made with Pure CSS3.
##Testing## Install old Chrome Versions without overwriting your settings.