54 cards where the name includes “marsh”

Air Marshal (The Brothers' War #43)
Angelic Field Marshal (Commander Masters #13)
Benalish Marshal (Game Night #8)
Blooming Marsh (Outlaws of Thunder Junction #266)
Cinder Marsh (Tempest Remastered #236)
Dauntless River Marshal (Magic 2015 #8)
Dawnwing Marshal (Foundations #570)
Daysquad Marshal (Ikoria: Lair of Behemoths #8)
Éomer, Marshal of Rohan (The Lord of the Rings: Tales of Middle-earth #120)
Field Marshal (Tenth Edition #15)
Frost Marsh (Coldsnap #146)
Goblin Marshal (Urza's Destiny #85)
Grand Marshal Macie (Unfinity #168)
Graveyard Marshal (Core Set 2019 #99)
Haazda Marshal (Guilds of Ravnica #13)
Haunt of the Dead Marshes (The Lord of the Rings: Tales of Middle-earth #90)
High Marshal Arguel (Alchemy: Ixalan #24)
Marshaling Cry (Future Sight #13)
Marshaling the Troops (Portal Three Kingdoms #141)
Marshal of Zhalfir (March of the Machine #246)
Marshal's Anthem (Outlaws of Thunder Junction Commander #82)
Marsh Boa (Prophecy #118)
Marsh Casualties (Duel Decks: Zendikar vs. Eldrazi #54)
Marsh Crocodile (Planeshift #115)
Marshdrinker Giant (Eventide #69)
Marsh Flats (Modern Horizons 2 #248)
Marsh Flitter (Zendikar Rising Commander #46)
Marsh Gas (Fourth Edition #146)
Marsh Goblins (The Dark #93)
Marsh Hulk (Dragons of Tarkir #109)
Marshland Bloodcaster (Outlaws of Thunder Junction Commander #139)
Marshland Hordemaster (Alchemy: Bloomburrow #27)
Marsh Lurker (Tempest #144)
Marshmist Titan (Born of the Gods #76)
Marsh Threader (Worldwake #14)
Marsh Viper (Fifth Edition #315)
Mogg War Marshal (Dominaria Remastered #131)
Odric, Lunarch Marshal (Dominaria United Commander #103)
Persistent Marshstalker (Bloomburrow #104)
Piranha Marsh (Zendikar #222)
Ramosian Sky Marshal (Mercadian Masques #40)
Resplendent Marshal (Kaldheim #22)
Salt Marsh (Eighth Edition #325)
Seasoned Marshal (Duel Decks: Elspeth vs. Tezzeret #15)
Shipwreck Marsh (Innistrad: Midnight Hunt #267)
Sima Yi, Wei Field Marshal (Portal Three Kingdoms #82)
Skirk Fire Marshal (Duel Decks Anthology: Elves vs. Goblins #50)
Smoldering Marsh (Duskmourn: House of Horror Commander #299)
Steel-Plume Marshal (Jumpstart #5)
Stern Marshal (Portal #32)
Sunlit Marsh (Dominaria United #257)
Ulder Ravengard, Marshal (Alchemy Horizons: Baldur's Gate #76)
Urborg, Tomb of Yawgmoth (Tales of Middle-earth Commander #375)
Vivid Marsh (Commander 2017 #292)

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