Almost every G.I. Joe and Cobra character cameos at some point in this thick sized Devil's Due graphic novel. I'm not sure calling it an omnibus is correct. It's nowhere near as big as the Marvel or DC Omnibus (omnibi?) are. But it is an extra thick graphic novel (though not oversized).
Cobra has taken M.A.R.R.S. away from Destro and the Baroness and are using the advance weaponry to destabilize most of the world's hot spots. The world breaks into World War III while G.I. Joe is deployed internationally to get to the bottom of it. Then, to further escalate the war, Cobra nukes Boston.
The story is fine and virtually every living Joe and Cobra has at least a brief cameo. Those most heavily featured are: Snake Eyes, Storm Shadow, Agent Delta (you'll just have to read it), Shipwreck, Cover Girl, Duke, General Hawk, Wild Bill, Spirit, Destro, James McCullen Destro, The Baroness, Firefly, Roadblock, Scarlett, Cobra Commander, Tomax & Xamot, Billy (Cobra Commander's son who meets his end), and Zartan.