Check out this thread
Can materials share same centralized base color?
Edit: like CarlG’s answer, with node groups you can do more than just a colour value.
Edit 2: I have been playing around with the node group method.
I added a colour as a costom property to the cube and used that property to drive each chanel of an rgb node and made a node group with it.
Then I added that node group to the other objects and changed the colours of the objects with a hue sat node.
Then I added a wave texture to the node group and a few simple math nodes using the rgb value.
Now the colour of the cube changes the colours and the wave pattern of the other objects 
Silly but fun!
