That is the plane that everybody is on, and its effects apply to all players
Many collectors prefer zippered binders because they offer better dust and moisture protection

Drawing Cards with Nymris | Commander | Jason Alt Commander (1) 1 Nymris, Oona's Trickster Creatures (21) 1 Brazen Borrower 1 Brineborn Cutthroat 1 Crafty Cutpurse 1 Cunning Nightbonder 1 Dream Eater 1 Hullbreacher 1 Lochmere Serpent 1 Naiad of Hidden Coves 1 Nimble Obstructionist 1 Notion Thief 1 Opposition Agent 1 Portal Mage 1 Slitherwisp 1 Snapcaster Mage 1 Spectral Sailor 1 Stunt Double 1 Thassa's Oracle 1 Torrential Gearhulk 1 Venser, Shaper Savant 1 Voracious Greatshark 1 Wavebreak Hippocamp Planeswalkers (1) 1 Jace, Wielder of Mysteries Instants (31) 1 Aetherize 1 Arcane Denial 1 Brainstorm 1 Commandeer 1 Counterspell 1 Countersquall 1 Cyclonic Rift 1 Deadly Rollick 1 Desertion 1 Dig Through Time 1 Drown in the Loch 1 Fact or Fiction 1 Fierce Guardianship 1 Frantic Search 1 Gather Specimens 1 Go for the Throat 1 Impulse 1 Mana Drain 1 Mystical Teachings 1 Mystical Tutor 1 Narset's Reversal 1 Negate 1 Opt 1 Pongify 1 Rapid Hybridization 1 Reality Shift 1 Rewind 1 Spelljack 1 Swan Song 1 Unwind 1 Vampiric Tutor Enchantments (4) 1 Faerie Tauntings 1 Omen of the Dead 1 Omen of the Sea 1 Rhystic Study Artifacts (9) 1 Arcane Signet 1 Charcoal Diamond 1 Dimir Signet 1 Fellwar Stone 1 Mind Stone 1 Sky Diamond 1 Sol Ring 1 Talisman of Dominance 1 Thought Vessel This almost feels like a tribal deck to me - we have Cunning Nightbonder and Niad of Hidden Coves reducing the cost of our "flash tribal" cards and that's as many warchiefs as most tribes get

If you dont care about that part, this is just an awesome payoff for paradox-style decks, giving you free copies of spells cast from various zones
Finally, early information indicates a Premium Bandai Japan lottery-style distribution, which naturally increases collector attention because not every buyer may be able to obtain it directly
I dont believe the bulbous look of the changelings is mutually exclusive to the changeling mechanic, but would understand if that visual marker in the art is needed to tie the creatures together across the games history