EVs: 4 HP/252 SpAtk/252 Speed
-Water Pulse/Ancient Power/Weather Ball
Hurricane is obviously going to see more use on Rain teams, and rain also gives Articuno more power against Fire- and Rock-types.
Ah yes, the first of the legendary birds, and the first legendary Pokemon overall. Articuno is the first legendary Pokemon most players will ever meet, most by virtue of the observation deck binoculars east of Fuchsia City in the original gen 1 games:
Sadly Articuno is the weakest of the 3 birds, and arguably the least popular despite its crisp and beautiful design. Ice/Flying is terrible defensive typing, leaves you extremely vulnerable to Stealth Rock, and doesn't have the widest movepool. But you can still run a few fun sets, and with the addition of a regional variant it has received some renewed interest these past few years.
A gimmick set that turns the random chance of the 1 hit KO Sheer Cold into absolute certainty with Mind Reader. Although if your opponent switches out the 100% accuracy boost is moot, so I suppose you are still gambling. Hurricane also pairs nicely with Mind Reader and has a much higher chance of connecting if your opponent swaps out expecting a Sheer Cold. Blizzard works similarly, but if you want to focus on survivability you can sub in Roost.
A straightforward boosting sweeper for the Galarian variant. Set up Calm Mind to boost power output, pick your Psychic STAB of choice depending on preference, have Air Slash be your back up STAB with added flinch support, and round out neutral coverage with Shadow Ball. Boost damage further with Life Orb, and your nature/EVs are poured into special attack and speed.
A Stored Power set. Get in as many Calm Minds as you can, using Recover when needed, and then unload boosted Stored Power onto your opponent. Air Slash functions as a back-up offensive option against targets that resist or block Stored Power, but if you feel confident you won't be blocked by Dark types you can sub in Agility which will solve your speed control issues all while still adding to Stored Power's base power. Leftovers keeps Articuno around longer, and a Bold nature in tangent with max EV HP and defense alongside the special defense boost of Calm Mind ensure that this arrogant bird is as sturdy as possible against opposing threats.
Articuno has had one of the hardest falls from grace ever experienced in Pokémon. A Superstar in Red/Blue/Yellow thanks to it having a sky high base 125 Special, 90% Accurate Blizzards that were not resisted by Fire allowed Articuno to smash the metagame by spamming its STAB. Then come generation 2, Blizzard was nerfed to 70% accuracy and now Fire types resisted Ice. But that was nothing compared to the Special split moving that meaty base 125 Special to Special Defense. Really Game Freak? Defensive Ice types just don't work, they need to be on the offense. And if that wasn't enough, Stealth Rocks introduced in Gen 4 eat half of Articuno's HP. Articuno has since languished in the depths of usage, spared a passing glance thanks to its former glory, but then we are reminded of its horrid typing and go on our way.
Generation 8 has been kind to Articuno with the Introduction of Heavy Duty Boots. No longer maimed by Stealth Rock, Articuno can actually try to wall things now, as 90/100/125 defenses are pretty good and reliable recovery in Roost makes Articuno all the better at walling. However, Ice Flying ranks among one of the worst Defensive typings in the game, so Articuno must tread carefully lest it be shattered by a super effective move.
Bird Hidden in the Mist
Ability: Pressure Item: Heavy Duty Boots
-Toxic Nature: Timid (+SPE, -ATK) EVs: 4 DEF / 252 SATK / 252 SPE
Set aiming to take advantage of Articuno's great natural bulk. Substitute and Roost are a fantastic combo, allowing Articuno to tank repeated attacks via Substitute, recover the Sub damage with Roost and setup again. Pressure just further tips the equation in Articuno's favor, draining the PP of powerful moves, so if your opponent can't break through the Substitutes in time, they may lose their answer to Articuno. Articuno's special bulk comes in handy as well, easily tanking the Sound moves that bypass Substitute, while Substitute patches up the issue of Tanking pokémon being vulnerable to Status. Toxic is an important component of this set, punishing setup sweepers who think they can use Articuno as setup bait. Freeze Dry rounds out the set, an excellent Ice STAB move that strikes Water types down leaving Steel types as the one true counter to this set.
EVs are to max out speed as you want Articuno to be able to throw up a Substitute before attacking. Max Special Attack is necessary to prevent Articuno from being too passive.