55 cards where the set is “paer” and the cards are cards with a date stamp

Aethergeode Miner (Aether Revolt Promos #4s)
Aethersphere Harvester (Aether Revolt Promos #142s)
Aethertide Whale (Aether Revolt Promos #27s)
Aetherwind Basker (Aether Revolt Promos #104s)
Aid from the Cowl (Aether Revolt Promos #105s)
Ajani Unyielding (Aether Revolt Promos #127s)
Baral, Chief of Compliance (Aether Revolt Promos #28s)
Baral's Expertise (Aether Revolt Promos #29s)
Battle at the Bridge (Aether Revolt Promos #53s)
Call for Unity (Aether Revolt Promos #9s)
Consulate Crackdown (Aether Revolt Promos #11s)
Dark Intimations (Aether Revolt Promos #128s)
Disallow (Aether Revolt Promos #31s)
Exquisite Archangel (Aether Revolt Promos #18s)
Freejam Regent (Aether Revolt Promos #81s)
Glint-Sleeve Siphoner (Aether Revolt Promos #62s)
Gonti's Aether Heart (Aether Revolt Promos #152s)
Greenbelt Rampager (Aether Revolt Promos #107s)
Greenwheel Liberator (Aether Revolt Promos #108s)
Heart of Kiran (Aether Revolt Promos #153s)
Herald of Anguish (Aether Revolt Promos #64s)
Heroic Intervention (Aether Revolt Promos #109s)
Hope of Ghirapur (Aether Revolt Promos #154s)
Indomitable Creativity (Aether Revolt Promos #85s)
Inspiring Statuary (Aether Revolt Promos #160s)
Kari Zev's Expertise (Aether Revolt Promos #88s)
Kari Zev, Skyship Raider (Aether Revolt Promos #87s)
Lifecrafter's Bestiary (Aether Revolt Promos #162s)
Lightning Runner (Aether Revolt Promos #90s)
Mechanized Production (Aether Revolt Promos #38s)
Merchant's Dockhand (Aether Revolt Promos #163s)
Metallic Mimic (Aether Revolt Promos #164s)
Midnight Entourage (Aether Revolt Promos #66s)
Oath of Ajani (Aether Revolt Promos #131s)
Paradox Engine (Aether Revolt Promos #169s)
Peacewalker Colossus (Aether Revolt Promos #170s)
Pia's Revolution (Aether Revolt Promos #91s)
Planar Bridge (Aether Revolt Promos #171s)
Quicksmith Rebel (Aether Revolt Promos #93)
Quicksmith Rebel (Aether Revolt Promos #93s)
Quicksmith Spy (Aether Revolt Promos #41s)
Release the Gremlins (Aether Revolt Promos #96s)
Rishkar, Peema Renegade (Aether Revolt Promos #122s)
Rishkar's Expertise (Aether Revolt Promos #123s)
Scrap Trawler (Aether Revolt Promos #175s)
Secret Salvage (Aether Revolt Promos #71s)
Solemn Recruit (Aether Revolt Promos #22s)
Spire of Industry (Aether Revolt Promos #184s)
Sram, Senior Edificer (Aether Revolt Promos #23s)
Sram's Expertise (Aether Revolt Promos #24s)
Tezzeret the Schemer (Aether Revolt Promos #137s)
Walking Ballista (Aether Revolt Promos #181s)
Whir of Invention (Aether Revolt Promos #49s)
Yahenni's Expertise (Aether Revolt Promos #75s)
Yahenni, Undying Partisan (Aether Revolt Promos #74s)

In the blink of an eye, they strode from deep snow to the end of this search.