Card Sleeves and Cases Protect your cards with the help of a princess and a prince (in training)
you dont put them in your deck or sideboard

Aarakocra Sneak Abigale, Eloquent First-Year Abigale, Poet Laureate Abzan Skycaptain Aegis Sculptor Aerial Extortionist Aerie Auxiliary Aerie Mystics Aesthir Glider Aetherstorm Roc Airdrop Condor Akim, the Soaring Wind Ambrosia Whiteheart Anvilwrought Raptor Apex Hawks Aphetto Vulture Arcanist's Owl Arcbound Condor Arctic Aven Artificer's Assistant Ascending Aven Augury Owl Augury Raven Aven Archer Aven Augur Aven Battle Priest Aven Brigadier Aven Cloudchaser Aven Courier Aven Envoy Aven Eternal Aven Farseer Aven Fateshaper Aven Fisher Aven Fleetwing Aven Flock Aven Fogbringer Aven Gagglemaster Aven Heartstabber Aven Initiate Aven Interrupter Aven Liberator Aven Mimeomancer Aven Mindcensor Aven Redeemer Aven Reedstalker Aven Riftwatcher Aven Sentry Aven Skirmisher Aven Smokeweaver Aven Soulgazer Aven Squire Aven Sunstriker Aven Surveyor Aven Tactician Aven Trailblazer Aven Trooper Aven Warhawk Aven Wind Guide Aven Wind Mage Aven Windreader Aven of Enduring Hope Avian Oddity Baleful Strix Balmor, Battlemage Captain Balshan Collaborator Bartz and Boko Battlefield Percher Battlefield Raptor Battleflight Eagle Battlewing Mystic Battlewise Aven

In Vintage, one of the only formats where the Power 9 are legal, players are limited to one copy of each Power 9 in their deck
That covers creatures, of course, but also Food, Treasures, Clues, and all the other artifact tokens that have made themselves at home in recent Magic