With access to Coil, a move that boosts Attack, Defense, and accuracy, as well as a high-powered STAB move, Arbok can become very threatening after a single boost. Arbok utilizes its good defensive typing and Coil to set up against a variety of offensive and defensive Pokemon, boosting its Attack while simultaneously making it harder to revenge kill. Gunk Shot is the main STAB move, and it works very well in conjunction with Coil, which brings its shaky 70% accuracy up to 91% after just one boost. Sucker Punch gives Arbok a way of defeating the faster Pokemon that try to revenge kill it. In the last slot, Earthquake can be used for coverage against Steel- and Rock-types, but Seed Bomb can be used instead in order to hit Ground-type Pokemon for super effective damage without losing coverage against Rock-types.
Both of Arbok's abilities are good, and the one you use should depend upon the role you'd like Arbok to play. Intimidate is the preferred ability if you want Arbok to succeed against offensive teams, as it allows Arbok to come in against most Fighting-type Pokemon, including as Primeape, Gurdurr, and Sawk that are locked into Close Combat, and use them as to set up. Shed Skin, however, can be used to let Arbok function more as a stallbreaker, letting it set up multiple times against a variety of bulkier Pokemon thanks to how well it can shrug off a burn or paralysis. Aside from the moves listed above, Rest can be used in conjunction with Shed Skin, allowing Arbok to heal up and hopefully wake up early. However, it would force Arbok to choose between coverage and priority, meaning it would have a harder time against either defensive or offensive teams. Aqua Tail is a usable move in the fourth slot to hit Ground-types while still retaining coverage on Steel-types, but it doesn't hit Steel-types hard enough and would lose out on coverage against Seismitoad.
While this set is fairly powerful, it struggles against bulky Ghost- and Psychic-type Pokemon. Liepard makes for an exceptional teammate, as it is able to Pursuit trap these Pokemon and can even Encore setup sweepers such as Calm Mind Musharna that would normally set up against Arbok. Arbok returns the favor by defeating the Fighting-types that plague Liepard. If Seed Bomb is used, Steel-type Pokemon such as Metang, Klang, and Bastiodon will be problematic—Klang can even set up alongside it. Therefore, Pokemon that can get rid of them, such as Golurk and Seismitoad, make for good partners. However, if Earthquake is chosen, Ground-types such as Piloswine and Golurk become an issue, making bulky Water-types, such as Ludicolo and Seismitoad, good partners to defeat them.