When talking about higher power levels, Id be remiss to omit Mana Crypt
It allows for easy organization and viewing of the collection
Printed in 1993s Alpha set, this artifact introduced a completely unique gameplay mechanic: physically flipping the card onto the battlefield
For example, FF4 's Cecil and Kain both have their stories told in their respective cards - Cecil starts as a dark knight that loses the owner life and transforms into a paladin with lifelink to restore what was lost, whereas the complex character that is Kain betrays the party and becomes an enemy, which is represented by being a card that changes owners
Spiteful Repossession can be as fair or as unfair as you want it to be, which makes it a real highlight for me
Shantotto, Tactician Magician A limited focused card for the UR cast big spells archetype which seems like a perfectly decent little dude, who also loves affinity for artifacts