Hey Chris -
You'll generally find that Tableau doesn't include "industry & performance specific" palettes like RAGG / BRAG / RAGB. While this stuff is arguably very important to some, it's not top of the list for most Tableau users and would simply clutter the UI for them.
Never fear, though - Tableau has allowed one to add custom color palettes for a long time. Here are few things to get you started:
Hope this helps.
Also, it sounds like your measures are Continuous and not Discrete, thus the color fade from one to another.