mtg shrine cards card 'The Great Unbinding' explains creature type where X is the number of cards in all graveyards with the same name as that spell. The Best Shrines in Magic:

Scaling with the amount of Poison Counters on opponents, Phyrexian Swarmlord can create oodles of Phyrexian Insect Tokens

Committing a crime requires targeting something an opponent controls, and they control their own spells on the stack

Sisay, Weatherlight Captain is the most popular leader of this archetype, and I like that option

Even better, it has the Hideaway ability, letting you dig five cards deep into your deck and tuck away a spell, ready to cast it for free later when you meet a particular criteria: in this case, having three creatures with different powers after you tap Collector's Cage

Card draw like the staple Pawpsicle, Develop Your Brain, and the damage/draw combo of Let The Storm Rage On would fit in nicely