CSS3 has been a preferable choice for website owners for many a reasons. If you are planning to speed up the workflow and in favor of CSS3, you may find following tools very much useful.
If you love tweaking your site here and there, then CSS3 Please! is the best option for you. Basically it is a rule generator that works as a playground. You can make different CSS3 tweaks and copy and paste it to your own file.
CSS3 Button Maker is one of my favorite tools. It gives you more options of sliders and color pickers to style your CSS3 button. Simply you have to take hold of the code and use it in your own project.
CSS3 Generator provides you with codes. After selecting from a list of CSS3 properties, you have to fill in the parameters as per your requirement. Then the CSS3 Generator spits out the generated code and you can see a live preview also.
CSS3 Transforms provides you with a few sliders. There you can try out different transforms like position, rotation, skew and many more. You can also find respective codes on the fly.
CSS3 Gradient Generator
CSS3 Gradient Generator is a display case of the power of CSS based gradients and a tool for designers and developers to create a gradient in CSS.
Here is a CSS Gradient Generator that you can use.
CSS3 Selectors Test
CSS3 Selectors Test does a wonderful job of running a large number of small tests to decide that your browser is compatible with a number of CSS selectors. It detects the selectors those are not well matched and show them as marked.
You have to click on those CSS selectors to view the results, with an example and clarification of the tests.
But still CSS3 is not fully supported by all the browsers, so just keep an eye on what effect your css tweaks have on the behavior of your site on different browsers.