I just picked up the Arena Battle Accessory Set. It is a pretty cool set. You get a red Battle Droid that is the same as the Security Battle Droid. It doesn't have a backpack. There is a Battle Droid Blaster for him. There is also a red backpack that fires 2 missiles that fits on the Droid. The missiles go pretty far and you can rotate the launcher to fire in different directions. The set also has 2 Jango blasters, Jango's helmet, a clonetrooper rifle, 3 handcuffs, Jedi Cloak, and 2 lightsabers. The one lightsaber hilt is the same as Shaak's with a blue blade as well. The other is a Plo hilt with a green blade. I'm not sure who the cloak fits on. It doesn't fit on Plo but he is the only one I've tried to put it on.
Overall it is a pretty fun set and nice for army builders. The extra lightsabers are cool as well. 8/10