Oh snover, harbinger of hail in every lower tier he's allowed in. One look at his stats pretty much sum up that he's going to be used just for his weather, but oh what a potent thing hail is in this meta. With no other auto weather inducer to rain on his parade he is unchallenged as the best weather starter in the tire, and in the interest of utilizing the team slot for a productive set I'v found that the 2 best are scarf and sub seed.
4Atk / 252SpAtk / 252Spd Mild nature
-Hidden Power Rock/Fire
Blizzard is the main move you should be spamming as a 120 bp move with 100% accuracy is nothing to laugh at, and ice is a pretty solid attacking type. Giga Drain Is useful for water types that resist Blizzard, plus i useful for recovering some HP. The hidden power of choice is used for other hail teams mainly, with fire smacking opposing Snovers around or rock one of the slower ice types such as Walrein. Because of the bulk of most slow ice types I'v found HP Fire to be more useful, and most fire types that HP Rock could hit usually out speed it. Ice shard is good for a parting shot on things like Aerodactyle and other faster threats that can 1HKO our little Christmas tree without breaking a sweat, putting some hurt on and bravely sacrificing itself for one of it's fellow blizz spammers to come in. The nature maximises Snovers SpAtk without jeopardizing Ice Shards power, and the reduced defences doesn't matter much considering it's probably going to take huge damage regardless.
Unfortunately, for all this, Snover is still very slow and prone to revenge killing. It's paper thin defenses only serve to magnify this problem, meaning as a pure scarfer it's completely out outclassed by other scarfers such as Rotom-Mow or Manectric and can't just be slapped on a team as a revenge killer.
Being as how this is to be used on an offensive team as a lead good pokes to compliment this would be powerful Blizzard spammers such as Glaceon, Rotom-Frost, and Jynx to take advantage of 100% accuracy Blizzards. A powerful fire type such as Entei or Rapidash usually synchronizes well with hail teams and offer a fantastic counter to opposing hail teams, even though they wont be immune to the hail.
252HP / 4Def / 252SpDef Calm Nature
- Leech Seed
- Protect / Giga Drain
This set, unlike the other set that just tries to hit hard and either get out or die, seeks to stick around and pester the opponent as much as possible for as long as possible. Leech seed and Substitute form the crux of this set, offering reliable recovery and slow damage to further wear down opponents along with hail damage, and Substitute seeks to act as a buffer for powerful attacks. Blizzard is used so that Snover isn't complete Taunt bait, and because it still does a decent amount of damage even without investment. Protect is usually the better option and is used to stall out even more turns of hail and leech seed recovery damage, although Giga Drain can also be used if you'd like a move that gives you even more recovery. The given ev's are tho maximize Snover's staying power and maximizing his better SpDef stat.
The downside is that this set, like the scarf set, is also severely outclassed as a pure sub seeder. Lackluster defences and slow speed means it's even more prone to revenge killing. Cincinno is the bane of this sets existence, out speeding and delivering a OHKO Snover even when behind a Substitute. Whimsicott has prankster and a better support movepool, and even more bulk than Snover; while Sceptile is also much faster and has a much greater offensive presence.
This set can be used on an offensive or stall team easily. Powerful Blizzard spammers such as Glacion, Rotom-Frost, and Jynx once again act as great partners, although more stall based partners such as Walrein, Regice, and Overcoat Mandibuzz also fit well as a hail stall team. Support Nidoqueen is also quite useful for the always helpful stealth rocks, along with toxic spikes to wear down the opposition.
So, in conclusion, Snover is not a Poke just tossed onto a team willy nilly. It's instead used as the crux of a very effective play style thanks to it's ability to summon permanent hail, and so therefor whatever set is used is just used to somewhat make up for the otherwise down slot. A team has to be built around this little terror to fully exploit the hail, and so his main function is to get up hail and either annoy the opponent or act as a suicide lead and pave the way for a host of deadly sweepers and stallers hailing from the frozen North to proceed to clean house.