I frequently am in need of color gradients that aren't readily available through ArcGIS or the ColorBrewer add-in. I find the process of manually creating gradients in Arc very tedious: saved custom colors don't come up in the edit color ramp window.
I am wishing that there was some way to use Python to batch generate colors ramps for ArcGIS. For example, if I gave it a "high" color and a "low" color, it could create and import a linear gradient between the colors. Importing might simply be a matter of saving to a specified directory.