I feel Permeate is the most OP card right now.
I also think Caged Savaged is OP, but that's for another discussion.

Permeate needs nerf.

To provide the context, here are some alternative attachments that gives 2 attack buff.

Relentess Savagery

Probably the closet to Permeate. But it only returns to hand when the ally is killed. That makes it less usable.

Mindless Ferocity, Burning Hatread

Have some limitation. Even without it, it still wouldn't compare with Permeate.

Aura of Retribution, Strength of Conviction, Inner Strength

Just 2 attack buff. Inner Strength is 3cc, so it's inferior in every way.

Sacred Fire Walker

Gives Flame Splitter like ability so it's better than normal buff. But since it deals 1 arcane and 1 fire damage, it's useless against allies like Gargoyle

As you can see, Permeate is ridiculously more powerful than other attachments. You might say that old attachments are were generally unusable and more recent attachments are simply better designed. That may be true.

But you can also compare Permeate with abilities that deal 2 damage.

Static Shock, Shocking Grasp, Righteous Strike (3cc), and Sinkhole come to my mind.

I know they don't just deal 2 damage, but fundamentally they are just one time ability. The only advantages that these abilities have over attachments are it can be summoned on turn 2, you don't need an ally, and it can ignore stealth. Otherwise, attachments are better because it persists as long as the ally lives.

Possible nerf

- 2cc -> 4cc
- Only activates the ability when the ally is killed.
- 2 attack -> 1 attack