Uniform has a global color and material palette you can reference from procedural layers. You can use this palette to change the colors of all assets in a workspace from a single place. This allows fast color adjustments and generating color and material variations for assets.

You can find the Reference palettes in the References inspector. Tap on a reference (it should turn blue) to activate it. You can now use the Object -> Reference tool to add the active reference to the object as a procedural fill layer.

Like with any other procedural layer, you can now paint the layer mask to control the area of influence of the reference.