uiGradients is a very useful tool offering an ever-growing collection of gradients for designers. Even though gradients are not as popular as they used to be a few years ago, the trend is slowly coming back, so a tool like this can prove very useful.
You can add your own gradient or browse the already added ones from the collection. You can also download the code needed to create the gradient in CSS.
This tool is absolutely free to use.Visit uiGradients