Other Options

An alternative SubSeed set using Taunt and Hex is an option; notably, this prevents Taunt Yveltal, Whirlwind Ho-Oh, Blissey, and Roar Kyogre from breaking through, and it gives Calyrex-S a higher-PP attack to work with. The problem is that this set relies on teammates to spread status and set entry hazards to take off, as lacking Nasty Plot makes it harder to pressure the opposing team. Pollen Puff is a niche option to hit Zarude and Tyranitar switch-ins harder. Will-O-Wisp could be run to cripple common switch-ins such as Yveltal, but it simply does not provide as much utility as Aromatherapy or Nasty Plot does.

Checks and Counters

Yveltal: Heavy-Duty Boots Yveltal can switch into any attack and proceed to force Calyrex-S out. Yveltal lacking Choice Scarf needs to be wary of Trick, as this can force the team into very difficult situations, especially in combination with entry hazards or status. Sets lacking Snarl, Taunt, or an Attack-invested U-turn will lose to SubSeed Calyrex-S, and only the bulkiest of Yveltal will avoid the 2HKO from +2 Draining Kiss. Even still, Calyrex-S must always be wary of Sucker Punch.

Dark-types: Dark-types besides Yveltal such as Zarude and Tyranitar are bulky enough to take Astral Barrage and force Calyrex-S out. These Pokemon have worse recovery options than Yveltal, and they must also be wary of Trick. The rare Pollen Puff will do massive damage to them, as well. Offensive Dark-types such as Urshifu-S, Weavile, and Hydreigon can bring some security against Calyrex-S on more offensive teams.

Normal-types: Blissey fears Psyshock, but it can switch into a Choice-locked Astral Barrage with impunity. The rare Porygon2 completely walls most Calyrex-S. Both Pokemon are severely crippled by Trick, albeit giving Calyrex-S a useless item instead of Heavy-Duty Boots.

Priority: Marshadow and Giratina-O can help to keep Calyrex-S at bay with Shadow Sneak. They cannot take Astral Barrage at all and thus can only revenge kill Calyrex-S.

Strong Special Tanks: Ho-Oh and Kyogre have enough special bulk to force Calyrex-S out in a pinch. They can phaze SubSeed sets with Whirlwind or Roar. However, both will get 2HKOed by Choice Specs Astral Barrage and they cannot take boosted hits. Trick also severely limits them.

PP Stalling: Eternatus, but also some lesser-used Pokemon such as Dialga, Palkia, and Weavile, have Pressure, which can quickly lower Astral Barrage's already low 8 PP. Normal-types such as Blissey can also switch into Astral Barrage for free. This can be critical to stopping a Calyrex-S sweep.