Watercolor Renderer is a real-time watercolor renderer for Blender, built by Pixel Egg Studio to let artists direct how the watercolor style should look. Control happens in two ways: global configs and local vertex painting.
Global configs set how the whole scene should look, with options like canvas type, canvas roughness, and pigment density. Local vertex painting provides five types that simulate different characteristics of watercolor: Pigment Turbulence, Pigment Granulate, Color Bleeding, Edge Darkening, and Substrate Distortion. While global configs affect the whole scene, vertex painting affects a particular mesh and its vertices, so you can make micro adjustments to the look you want.
The package ships as an addon zip file along with some demo scenes as blend files. It works on Windows 10/11, macOS, and Linux, targets Blender 4.0 to 4.5, and is distributed as a GPL add-on.