On the bottom, is Professor Oak's New Theory
Here is every Commander Legends: Battle For Baldur's Gate precon deck, ranked from worst to best
Julius Jumblemorph Ego Erasure Feisty Spikeling Firdoch Core Fire-Belly Changeling Flock Impostor Formless Genesis Game-Trail Changeling Gangly Stompling Ghostly Changeling Gladewalker Ritualist Graveshifter Guardian Gladewalker Impostor of the Sixth Pride Irregular Cohort Littjara Littjara Glade-Warden Littjara Kinseekers Masked Vandal Maskwood Nexus Mirror Entity Mischievous Sneakling Mistform Ultimus Mistwalker Moonglove Changeling Moritte of the Frost Morophon, the Boundless Mothdust Changeling Mutable Explorer Nameless Inversion Omni-Changeling Omo, Queen of Vesuva Overlord of the Hauntwoods Personify Prideful Feastling Realmwalker Rooftop Percher Runed Stalactite Shapesharer Shields of Velis Vel Sizzling Changeling Skeletal Changeling Springleaf Parade Stalactite Dagger Taurean Mauler Three Tree Mascot Turtleshell Changeling Universal Automaton Unsettled Mariner Valiant Changeling

Originally debuting in Force of the Breaker , Jesse Andersons Crystal Beasts are back in a big way with many new cards, including a new form of Rainbow Dragon as a Fusion Monster that can reach 11000 ATK, clear the field, and unleash your banished Crystal Beast monsters for a devastating final blow
One example is a deck using the Paradox Brothers and the Guardian trio to stall out Leo until you have enough monsters to use Union Attack on Gravekeepers Vassal for the win