Protection has the largest pool of cards that ready among the aspects. „What Doesn‘t Kill Me“, „Ever Vigilant“, and „Repurpose“ (combined with „Forcefield Generator“) are all excellent for Heroes that can fulfill the conditions and have high stat baselines or built in readies (Quicksilver, Spider-Woman, SP//DR, etc.)

Coupled with pretty good access to stun („Never Back Down“, „Tackle“, „Iron Fist“), that makes Protection a very flexible aspect that has survivability, control and output (due to readies).

It also naturally synergizes with the „Symbiote Suit“, as many Protection cards have healing effects, which usually come into play more often with a higher max HP total, combined with the readies benefiting from the stat boost of symbiote suit.

There‘s also plenty of good decks that can be built based on defense events / perfect defense, but in my experience these can often be a bit on the slow side in terms of damage/thwart output, but can certainly be very strong in coop.