Other than having to retroactively update dozens of previous cards - something done with some keystrokes in digital form - are there any downsides to creating the Book subtype
You can see all the revealed cards from Secrets of Strixhaven in the set's card image gallery
Not only do you get +2/+2 and protection from two colors, but you also gain two powerful abilities on the attack, and they will untap your lands, Raise Dead a creature, Shock something, and so forth
Channeler will have to attack every turn once Delirious, but this isnt much of an issue for tempo decks like Legacy Izzet Delver that are trying to end the game relatively fast
Did I miss any glaringly obvious choices
The right binder with EZD rings, hard covers, and premium trading card pages will keep your cards safely protected for decades