You can actually try putting a white board marker against a spinning yoyo and that creates a topyo-swirl-ish kinda look. You can just draw on yoyos to modify colors
Swirls
Splashes
Fades
Etc.
You can even put a marker against the rims so that the yoyo would look like a bimetal
Square Wheels was the first thing that came to my mind too, and the Rebel Macrocosm, which was a really wild thing with the unicorn skull and everything…
The silver one is also very interesting. They must have masked off a galaxy because that black “stripe” isn’t just dark… it’s full galaxy in the stripe bits!
This one was even earlier. Posted to Flicker in January of 2010 so it was done in 2009. If you go to the link you’ll see “For Dave”. That’s me. I asked Justin (Vendetta to anodize this for me).