Brand Color Guide
Many a time we work on projects or elements that require the specific colors of other brands, maybe mostly social these days. It allows us to, not only to serve the brand well, but also enables our audiences to recognize the brand element(s) quickly and clearly. For example, you may be building the interface of an app and need social media share buttons; you have the icons and need to decide to whether to use one color for all of them or apply their brand specific colors. Depending on your decision is how quickly (or not) users will recognize these elements. Even though these brands, and many others, have strong enough symbols as representatives, I believe color helps greatly in recognition.
In my own search for brand colors, I have found 2 brand color guide resources that provide an extensive list for your use.
http://brandcolors.net/ — allows you to search brands, provides its HEX code, allows you to download palettes, and share the page as well.
http://guidelinecolour.com/ — allows you to search brands, provides its HEX code, when available provides the Brand Guidelines