Keyframes gives you a visual timeline to help you create, view, and run animations without having to go back and forth between your browser and editor. And it gives you the CSS when you're done.
An accessibility-friendly random color generator for text & background combinations.
WebGradients is a free collection of 180 linear gradients that you can use as content backdrops in any part of your website.
Typeculator is a simple type scale calculator based on the "Golden Thread" technique.