CHALK was a extremely popular archetype during gen 6, to the point where iirc the top 8 teams at worlds that year were almost all identical, as by not playing CHALK (or a slight variant of CHALK with a antimeta adaptation) was basically making life harder for yourself for no reason.
By many considered the lowest point of VGC.
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It consisted of Cresselia, Amoongus, Landorus-Therian, Heatran, (Mega)Kangaskhan, hence the CHALK
https://pokeventurer.blogspot.com/2015/12/chalk-analyses-better-understanding.html
Compared to even SwSh final worlds
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Despite the omnipresence of Incineroar (by many considered by now the best VGC mon ever, though I think it'll have steep competition by Iron Hands next year), there is quite some variety in both pokemon choices and archetype, with both hard TR, semi TR and bulky offense showing up and a pretty healthy selection of support pokemon.
If you're curious, this was the day 2 usage for SV Worlds
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and the top cut
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More centralized than the year before, with Urshifu in all teams and Flutter Mane being "the mon to beat", most of them are BO though you do have a couple semi TR teams. Incidentally as I mentioned some posts ago, Hyperoffense is basically unplayable, you'd basically end up in "i either win at the lead or lose on the spot" in most matches due to not having switchins.
(It was pretty interesting how Lando-T went from basically unusable in reg D to being all over the place in reg E due to scarf tera flying being super strong into ogerbonk)