"Glaceon, the fresh snow pokemon!
By controlling its body heat, it can freeze the atmosphere around it to make a diamond-dust flurry."
-- Pokedex Entry for Pokemon Platinum

With pretty good Sp. Attack and Defense, Glaceon is a great addition to your team in pretty much any game! Jynx offers a better competetive option in Sword and Shield, but Jynx is freaky af whereas Glaceon is adorable.
What is the point in winning if you don't win in style?

My love for Glaceon started in my second run of Pokemon Platinum. First time around, I got a Leafeon as the mossy rock was closer lol. Whilst I do also love Leafeon, Glaceon has a larger share of my heart

Move Sets for Glaceon Must haves: Ice Beam -- 100% Accuracy and 90 Power Freeze Dry -- 100% Accuracy and 70 Power, but also super effective against water! Shadow Ball -- 100% Accuracy and 80 Power, no STAB but it gives a lil extra coverage that I find comes in handy! Optionals: Calm Mind -- Raises Sp. Atk, good for setting up to sweep. Quick Attack -- often comes in clutch! Blizzard -- 110 Power, but only 70% Accuracy. 100% Accuracy when snowing, or can be paired with: Hail/ Snowscape -- which brings Blizzard up to 100% Accuracy. Game-Specific: Tera Blast for Scarlet/Violet -- always a good move. 100% Accuracy, 80 Power, turns into whichever type your tera type is! Z-Celebrate for Sun/Moon -- get them sweet sweet buffs! Natures and EV Spreads Modest Nature (+Sp. Attack, -Attack) Does what it says on the tin. Glaceon has a good base Sp. Attack and doesn't need to use physical moves, so buff that Sp. Attk for the good dmg! Timid Nature (+Speed, - Attack) If you find yourself getting out-sped, might be worth going for timid, unless you want to rely on something like quick claw. EVs Max out both Special Attack and Speed to 252, and then dump the remaining 4 in Special Def or HP tbh.

Held Items Choice Specs Wise Glasses Choice Scarf Icicle Plate Icy Rock Never-melt Ice Leftovers Held items really depend on your overall build. Choice Specs are amazing, but have the drawback of only being able to use one attacking move. Would be good with hail/blizzard build. Choice Scarf can be good if you go for Modest Nature instead of Timid. I prefer wise glasses. Only gives you 1.1x boost to Sp. Atk, but I find choice specs (1.5x) limits me more than I like. I find myself using Icy Rock in Pokemon SV as it extends the number of rounds that snowscape lasts for. Berries for halving super effective attacks can be useful if you know you're gonna get targeted by them. Glaceon is weak to Fire, Rock, Fighting and Steel.