Swing has a special relationship with Silhouette which means they get to be the exclusive seller of these colors. As Swing Design also has an Amazon Store, you can find most of their selection there also (for those who prefer shopping through Amazon).
Swing Design is well known for their awesome Cameo Bundles, including:
Cameo heat transfer vinyl bundles
Silhouette adhesive vinyl bundles
Combination HTV adhesive bundles
Heat press and Silhouette Cameo bundles
At the time of writing, not all colors of Cameo 3 are available from Swing, but hopefully they are still making them and they will be back in stock soon!
This may be an indication that it’s going away soon, so if it’s the Silhouette color you like best, you better get in now!
So there you have it, all the Cameo colors!
The Cameo 4 is very new, of course, and so we can expect new colors in that model soon. Also, it’s likely that when the 15 & 20 inch Cameos are released in early 2020, they will have unique colors too.