Many Allies have triggered abilities (especially ones with the rally ability), allowing them to double up on the triggers so long as Katara is on the battlefield
Galvanic Discharge Sure, Galvanic Discharge seems powerful, but it always helps when evaluating cards like this to consider what the worst-case scenario looks like wait, Lightning Bolt
Vault 75: Middle School I evaluate Vault 75: Middle School as a one-sided board wipe since you choose the creatures in your deck and when to start chapter 1, and parts two and three are meaty gravy
Comprehensive Rules Cards with ninjutsu can enter combat tapped and attacking if the creature they swap with is unblocked
It has a CMC of 6 so they keep revealing cards
Its morph cost is only revealing a green card from your hand, which you can easily do over and over unless someone can force you to discard it