Weighing in at just 11KB, this lightweight MODX extra adds a ColorPicker Input Type to your Template Variables. Focusing on HTML5 and future browser support, Prism does not contain any theming files for rendering a colorpicker, it leaves that completely up to the browser.
Install Prism via the Package Manager or download here.
It's very simple, just extends the text type but with an input type="color" causing your browser (if supported) to render a colorpicker instead of a simple text field.
Does your browser support the HTML5 color input type?
Watch a screencast showing the HTML5 Color Input in different browsers and operating systems.