Theyre incredibly fast, theyre consistent, and theyre synergistic with cards like Nature's Lore, Three Visits, and Farseek
I get very into everything I do Ill preface this with the fact that I go as far as to sort my basic lands per set, my tokens alphabetically and I even know exactly where my keyword-counter, art cards and how to play magic info cards are

Amoeboid Changeling Avian Changeling Barkform Harvester Blades of Velis Vel Bloodline Pretender Cairn Wanderer Chameleon Colossus Changeling Berserker Changeling Hero Changeling Outcast Changeling Sentinel Changeling Titan Changeling Wayfinder Chitinous Graspling Chomping Changeling Crib Swap 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 Glade-Warden Littjara Kinseekers Masked Vandal Mirror Entity Mischievous Sneakling Mistwalker Moonglove Changeling Moritte of the Frost Morophon, the Boundless Mothdust Changeling Mutable Explorer Nameless Inversion Omni-Changeling Orvar, the All-Form Prideful Feastling Realmwalker Rooftop Percher Shapesharer Shields of Velis Vel Sizzling Changeling Skeletal Changeling Taurean Mauler Three Tree Mascot Turtleshell Changeling Universal Automaton Unsettled Mariner Valiant Changeling Venomous Changeling War-Spike Changeling Webweaver Changeling Wings of Velis Vel Woodland Changeling

Mega Swampert ex is Energy-hungry, and Mantyke helps set that up early thanks to its Splashy Toss
Her biggest strength is flexibility