Professional grading company PSA has established a system that evaluates trading cards on a scale from one to 10
ETB reveal your top X and put any number of Aura cards with mana value x or less directly on the battlefield
Elesh Norns cards seem to consistently outprice her fellow Praetors, and Id assume this stays the most expensive of the Multiverse Legends reprintings for a bit
Gray Ogre was printed in Limited Edition Alpha, when the base stats expected for a three-mana value creature were two power and two toughness
However, relying on a two-card combo can make your deck unbalanced, and will require you to invest in the Fighting-Type side of your deck as well as the Electric-Type
These decks often have several ways to tutor for and dig for the exact cards to win with, and the fewer the cards, the easier it is to pull off