This team is something I built for teambuilding shop back in late August (those who are part of that convo), but it was never posted. But, after seeing this teambuilding comp use Articuno to build around, I decided to refine that team down a bit more and post.
Articuno is very effective once you remove specially defensive walls that stop it (Regice, Grumpig, Lickilicky, Probopass), Fires that outspeed and check (Ninetales, Rapidash, Simisear), and Steel-types that wall its Ice and Flying coverage (Probopass, Metang, Klang) if Articuno isn't using Hidden Power Fighting. So, this team seeks to remove these answers to Articuno, and to give it the required support to be able to consistently set up with Agility and threaten with its LO boosted Dual STAB coverage moves. I'm using Freeze-Dry over Ice Beam for threats like Politoed and Relicanth to prevent being walled and forced out.
Articuno needs Defog support to be effective, which gave me the choice of Vullaby or Vibrava. While Vullaby isn't nearly as passive as Vibrava is, Vibrava doesn't stack SR weaknesses, is able to switch into common SR setters like Stunfisk and Probopass without being hit super effectively, and can either Defog or Earthquake on both of these targets. It has better type synergy with Articuno than Vullaby does, so it made for an easy pick. Its slow U-Turn also helps bring in Gogoat and Articuno for free, giving you ample opportunities to set up with either. Vibrava also counters other Rapidash for the team, which is useful for protecting Gogoat, Articuno, and my Rapidash / Probopass if it's running Drill Run.
Next, I wanted a fat SR setter that is able to remove Steel-types for Articuno, so Probopass worked well. With this spread, it traps even the fastest Probopass (this is faster than Sir Kay's Probopass in his possible sample team by 1 point). I actually don't like creeping with Probopass anymore since Piloswine is gone, so running as slow as 12 Speed is fine. Probopass also resists all of Vibrava's weaknesses to Ice / Dragon / Fairy, and gives the team a second, slow momentum-grabbing move in Volt Switch in addition to Vibrava's U-Turn.
Given Articuno removes defensive Grass-types like Tangela and Gourgeist-Super with ease, using Gogoat became a great option on the team. Gogoat is also here because it's an effective check to offensive Water types like Specs Floatzel and LO Simipour with its high Special Defense, especially given that the rest of the team (Probopass, Vibrava, Rapidash) wouldn't fare well against these two otherwise. The given spread lets Gogoat avoid the 2HKO from LO Simipour's Ice Beam:
252 SpA Life Orb Simipour Ice Beam vs. 228 HP / 196+ SpD Gogoat: 185-218 (41.6 - 49%) -- guaranteed 3HKO after Leftovers recovery
The rest of its EV spread gives you a Leftovers number, investing 56 EVs in Attack lets you OHKO Ninetales after +1 (from either Sap Sipper or BU) with Rock Slide after SR and gives you a better chance to OHKO Floatzel and Simipour via Horn Leech, the given Speed outspeeds 8 Spe Solrock so that you can Horn Leech before you're burned by WoW, and the rest is dumped into Special Defense. Its weaknesses are taken on well by the rest of the team: Fire is eaten up by Vibrava / Rapidash, Flying by Probopass, Ice by Probopass / Rapidash, Bug by Probopass / Articuno / Rapidash, and Poison by Vibrava / Probopass. BU Gogoat also sets up on SpDef Lickilicky, which gives the team some trouble otherwise.
At this point, the team was very slow and needed some immediate Speed in order to apply more offensive pressure. Rapidash is here given its ability to check Fire-types with Drill Run and Flash Fire, Steel-types and Regice with STAB Flare Blitz, Probopass via Drill Run, and it also lures Grumpig in (wanting to use its Thick Fat to sponge a predicted Flare Blitz) and OHKOes with LO Megahorn instead of losing out to Grumpig's T-Wave. Megahorn is optional to beat Grumpig, so its standard set with Wild Charge can still be used to beat threats like Pelipper and Swanna (Similarly, Gogoat can also use EQ over Rock Slide, but Rock Slide beats Jumpluff).
Finally, Mr. Mime is here to round out the team by giving both Articuno and Gogoat additional chances to sweep via Healing Wish, the team additional Speed overall, and a reasonably effective way to take out Steel-types like Probopass with Focus Blast if your opponent doesn't anticipate your moveset correctly. Zebstrika was in this spot originally, but I kept losing to Fraxure - so, Scarf Mr. Mime is here to revenge +1 Fraxure and keep the team safe from other speedy threats.
This team is overall very bulky with Milk Drink, 2 Roosts, Morning Sun, and Healing Wish to bring back whatever you need. Rate my nicknames, yn?