My favorite book, A Whack on the Side of the Head by Roger von Oech, is the book on creativity that did the most to steer me towards some answers
Bonehoard 4 Artifact Equipment Living weapon (When this Equipment enters the battlefield, put a 0/0 black Germ creature token onto the battlefield, then attach this to it.) Equipped creature gets +X/+X, where X is the number of creature cards in all graveyards
My personal belief is that once you add the 361st card you want to aim your design closer to the Modern Cube philosophy, though 540-card synergistic environments are definitely possible
What is more exciting is not these legendary cards
Ultimate Price Foil $0.45 Market $0.41 Price History Your Inventory Sign in to see your inventory Data Reserved List No All Time High $8.68 All Time Low $0.34 Foil Multiplier 1.00x Spread 97.8% Buy List $0.01 Nonfoil Daily $0.00 +0% Weekly -$0.01 -2% Monthly -$0.02 -4% Foil Daily $0.00 +0% Weekly -$0.01 -2% Monthly -$0.02 -4% Other printings Found In Different print Ultimate Price Instant Destroy target monocolored creature.
Ground Xeno has already seen success in the Yu-Gi-Oh