Omatsuri
Omatsuri, a little collection of free useful helpers.
The ultimate CSS tools for web designers | CSSmatic
Gradient generator, border radius, noise and box shadow
min-device-pixel-ratio test
What’s your device’s min-device-pixel-ratio?
Modular Grid Pattern
Useful web app to generate a grid pattern
20 Useful Tools for Responsive Web Design
Gridulator: Make pixel grids, lickety-split
Tell Gridulator your layout width and the number of columns you want, and it’ll spit back all the possible grids that have nice, round integers
CSS Border Radius
Try out border radius and copy/paste css
Conditional-CSS
Conditional-CSS allows you to write maintainable CSS with conditional logic to target specific CSS statements at both individual browsers and groups of browsers.