Are there any addons or other features in Blender that allow the Blender user to write nodes that passes in color ramps and reuse them in a group node? If the answer is yes, then what are the steps?
Single colors and vectors can be passed into a group node (reusable function). MixRGB node can simulate simple color ramp for two colors. So these items can be excluded from potential answers.
In response to a question below. A crude and compromised set of nodes. Candidate for enhancement and promotion to group.