http://www.techbomb.com/websafe/

Web safe color palette

https://www.colorspire.com/

https://www.colorspire.com/

https://www.cleancss.com/

Clean CSS is now available for more than just CSS. You can now beautify, minify, format, or compress many different file formats. Choose the tool below to get started.

http://topfunky.com/baseline-rhythm-calculator/

Baseline Rhythm Calculator

https://drewish.com/tools/vertical-rhythm/

CSS with vertical rhythm

http://css3generator.com/

CSS3 Generator

http://border-radius.com/

CSS Border Radius Generator