Random Color Node - Addon by mod3d brings a set of nodes to Blender for generating random and predictable colors in several ways. The scripts are written in OSL, the Open Shading Language, and the included documentation shows how to activate both the add-on and OSL.
The add-on offers three patterns. Rand generates pseudo-random values in a Min–Max range. Wave produces a smooth color transition along a sine wave. 3Range extends the Rand pattern with three Min–Max ranges and the ability to customize the distribution of values from each range.
A Light Version is also available, containing the Rand pattern with limited features plus documentation for that node. After installation, a copy of the node description is placed in the Blender Text Editor for reference. The add-on itself is under GPL-2.0-or-later, while the OSL scripts are distributed under BSD-3-Clause. A demo video is available.