The average number of other languages cards have been printed in since around 5th Edition is 8, but of course, some of these products, like Duel Decks and various Masters sets have far fewer languages of print, so well go with a slightly conservative average of 7, including English
There are tons of extremely powerful effects that become even better when doubled up, like Portal to Phyrexia's ability to force your opponents to sacrifice three creatures when it comes into play, now forcing all your opponents to sacrifice six creatures instead
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
It uses MTG cards in a self-contained multiplayer format with rules that are probably interchangeable with Commander
