The Dark Fetts, often known as simply Rogue Clones—though there were many other rogue clones—were a group of clone troopers that escaped Kamino in the Clone Rebellion.
They took whatever armor they could, sometimes stolen Phase IV suits from Stormtroopers, sometimes old Phase I suits. But they tried to maintain a system. Privates usually wore plain Phase I armor, with green marks. After reaching the rank of Lieutenant, they were allowed to customize their armor. Elite heavy troopers ('rail' ARCs') wore ARC trooper armor.
The Rogue's used modified CIS B-1s and B-2s, combining their designs with extra agility and fighting capabilities. All captains, and higher ranks, got a personalized droid, that they programed and customized (with the help of a technician).