The moon and stars decal you see is a pattern that was available last year on Crowns clothing.
We will continually change the Crowns clothing on a regular basis, so if you see something you like, buy it now!
As for the dye shop, there's only the one in Wizard City. If you prefer to adventure to areas that aren't quite so populated, try switching to a different Realm that has a lower population.
To do this, press Esc when you're not in a duel and click the tab on the right with two blue globes. There you will see a list of all the Realms (there are a few pages!) and the current population. Select a Realm and click 'Go To Realm'. You will be teleported to the exact same spot you are currently standing at but in a parallel realm.