At a whopping 200 damage, Crimson Storm is the most powerful attack in the game, with no cards having that many HP. However with the release of Space-Time Smackdown, it became possible to take damage from the strongest attack and survive. The latest pack, Triumphant Light, has not introduced any new ways of surviving Crimson Storm.

4th place: 180 HP + Giant Cape + Blue

This includes 4 cards: Blastoise ex, Machamp ex, Gyarados ex, and the man of the hour himself, Charizard ex.
These cards will just barely survive with 10 HP remaining. Fortunately none are weak to fire, which would make a difference here. I should also mention that if Charizard ex is powered up by Giovanni, none of these cards have a way to survive anymore. Some of you may note that Adaman provides even more damage reduction than Blue, however the current highest HP for steel types is 160, and they have fire weakness to deal with as well, so high HP + Giant Cape + Adaman doesn't keep anyone alive yet.

3rd place: Golem (Mythical Island) + Giant Cape

With its Guard Press attack, Golem can negate 30 points of incoming damage. At 180 HP with Giant Cape, this leaves it at 10 HP after Crimson Storm. Since Blue was not needed, we can factor in that Golem could use Blue to survive even if Charizard ex uses Giovanni. However, Golem most have gotten to attack during its previous turn in order to survive at all, keeping it from ranking higher.

2nd place: Mamoswine + Giant Cape

Mamoswine's ability Thick Fat provides 30 points of damage reduction from all fire and water attacks automatically, with no prerequisites. With the same HP and damage reduction as Golem, Mamoswine can also survive when Giovanni is in play with the help of Blue.

1st place: Bastiodon + flipping heads

Bastiodon's ability Guarded Grill provides a 50% chance to reduce incoming attack damage by 100. Bastiodon does have fire weakness so it's staring down the barrel of 220 damage from Crimson Storm (230 with Giovanni), but with 160 HP, that reduction is enough to leave it standing with HP to spare, even without the support of any other cards.

Some of you may wonder whether the 50% chance is actually better than just relying on one Giant Cape. I think statistically, drawing a Giant Cape in time is probably just a little more likely than 50% so it is a valid question. However, I still think Bastiodon deserves the gold medal:
None of the other cards can survive a second attack without the assistance of Dusknoir. The absolute max healing+damage reduction they can receive in one turn is 140 (Irida for 40, 2x potion for 40, 2x Butterfree for 40, Shaymin for 10, Blue for 10; they all already needed Giant Cape so they can't use it for another 20), which is not enough to survive again. Bastiodon only needs 90 (110 if both attacks use Giovanni) and another coin flip which is doable even without bench healers like Butterfree (though Blue or Adaman would need to reduce the first attack if Giovanni gets played). If Dusknoir is in play, Bastiodon can reduce the damage enough to keep it alive after one use, meaning Bastiodon could theoretically survive an incredible 4 rounds of Crimson Storms. It's entirely improbable and completely inadvisable, but distinctly possible, which is what earns Bastiodon the crown.

Honorable mentions

Cards that nearly made it

Venusaur ex, Probopass ex, Gengar ex, Pidgeot ex, Infernape ex, Gallade ex, and Garchomp ex.

Right now these cards are right on the threshold of survivability, and could survive with just 10 more points of damage reduction or HP increase. Venusaur ex and Probopass ex are also both weak to fire, so if they didn't have that weakness they would have made the list as well.

Cards that prevent attacks/damage

There are too many to list here and no easy way to search for them, so I'll just divide these into sub-categories and provide examples. Some cards prevent attacks (e.g. Vulpix), some cards become immune to damage (e.g. Dugtrio), and some cards inflict the status conditions Sleep, Paralysis, or confusion (e.g. Hypno, Dedenne, or Mismagius ex) which can all prevent a card from attacking, though some of these conditions require a coin flip. You could argue that these cards can "survive" a Crimson Storm, but since they do so by avoiding all damage in the first place it didn't really seem in the spirit of the list I'm trying to make. In theory, these cards could survive an infinite string of attacks under the right circumstances, which further highlights why I don't think they belong in the list but they did need to at least be mentioned.

Let me know if you think I missed anything!!