| MountainLegend of Blue Eyes White Dragon · 048 | Legend of Blue Eyes White Dragon | 048 | Common | €0.05 |
| Mountain WarriorUnlisted Printings | Unlisted Printings | — | — | — |
| Mount SylvaniaLegacy of the Valiant · 063 | Legacy of the Valiant | 063 | Super Rare | $0.72 |
| Mozarta the Melodious MaestraDuelist Alliance · 016 | Duelist Alliance | 016 | Rare | €0.30 |
| Mr. VolcanoPharaoh's Servant · 044 | Pharaoh's Servant | 044 | Common | €0.02 |
| Ms. JudgeThe New Challengers · 043 | The New Challengers | 043 | Short Print | $0.26 |
| Ms. Tick CallBeyond the Brave · 031 | Beyond the Brave | 031 | Common | €0.07 |
| Muckraker From the UnderworldDarkwing Blast · 051 | Darkwing Blast | 051 | Secret Rare | $1.20 |
| Mucus YolkPharaonic Guardian · 011 | Pharaonic Guardian | 011 | Common | €0.16 |
| Mudan the Rikka FairySecret Slayers · 017 | Secret Slayers | 017 | Secret Rare | €0.10 |
| Muddy MudragonDark Neostorm · 081 | Dark Neostorm | 081 | Rare | $0.37 |
| MudoraDark Crisis · 076 | Dark Crisis | 076 | Super Rare | €0.02 |
| Mudora the Sword OracleMagnificent Mavens · 026 | Magnificent Mavens | 026 | Ultra Rare | $0.28 |
| Mudragon of the Swamp2018 Mega-Tins · 005 | 2018 Mega-Tins | 005 | Ultra Rare | €0.21 |
| Muka MukaMetal Raiders · 107 | Metal Raiders | 107 | Rare | €0.05 |
| MukoSoul of the Duelist · 057 | Soul of the Duelist | 057 | Super Rare | $0.54 |
| Mulcharmy FuwalosRage of the Abyss · 024 | Rage of the Abyss | 024 | Secret Rare | €5.01 |
| Mulcharmy MeowlsSupreme Darkness · 025 | Supreme Darkness | 025 | Secret Rare | $0.45 |
| Mulcharmy PuruliaThe Infinite Forbidden · 027 | The Infinite Forbidden | 027 | Secret Rare | €2.92 |
| Multiple DestructionDuelist Pack: Battle City · 005 | Duelist Pack: Battle City | 005 | Ultra Rare | €1.05 |
| Multiple Piece GolemThe Duelist Genesis · 038 | The Duelist Genesis | 038 | Ultra Rare | $0.93 |
| Multiplication of AntsInvasion of Chaos · 098 | Invasion of Chaos | 098 | Common | €0.05 |
| MultiplyCrimson Crisis · 090 | Crimson Crisis | 090 | Super Rare | €0.12 |
| Multi TokenUnlisted Printings | Unlisted Printings | — | — | — |
| Multi-UniverseLegacy of Destruction · 086 | Legacy of Destruction | 086 | Super Rare | €0.07 |
| Munin the Runick WingsTactical Masters · 038 | Tactical Masters | 038 | Super Rare | €0.10 |
| Murmur of the ForestPhoton Shockwave · 058 | Photon Shockwave | 058 | Rare | $0.12 |
| Musakani MagatamaStorm of Ragnarok · 074 | Storm of Ragnarok | 074 | Rare | €0.17 |
| Muscle MedicCircuit Break · 041 | Circuit Break | 041 | Short Print | €0.10 |
| Muse-AUnlisted Printings | Unlisted Printings | — | — | — |
| Mushroom ManChampion Pack: Game Eight · 012 | Champion Pack: Game Eight | 012 | Common | €1.99 |
| Mushroom Man #2Metal Raiders · 114 | Metal Raiders | 114 | Common | €0.05 |
| Musical Sumo Dice GamesDimension Force · 047 | Dimension Force | 047 | Common | €0.04 |
| Musician KingMetal Raiders · 103 | Metal Raiders | 103 | Common | €0.02 |
| Mustering of the Dark ScorpionsDark Crisis · 093 | Dark Crisis | 093 | Common | $0.10 |
| Musto, Oracle of GustoDuel Terminal 6 · 081 | Duel Terminal 6 | 081 | Duel Terminal Rare Parallel Rare | $0.20 |
| MutamorphosisPhantom Nightmare · 070 | Phantom Nightmare | 070 | Secret Rare | $0.17 |
| Mutant MindmasterPhantom Darkness: Special Edition · 1 | Phantom Darkness: Special Edition | 1 | Super Rare | €0.17 |
| Mutiny in the SkyUnlisted Printings | Unlisted Printings | — | — | €0.13 |
| Mutually Affured DestructionIgnition Assault · 078 | Ignition Assault | 078 | Common | €0.10 |
| Muzurhythm the String DjinnStarter Deck: Xyz Symphony · 040 | Starter Deck: Xyz Symphony | 040 | Super Rare | €0.07 |
| M-Warrior #1Legend of Blue Eyes White Dragon · 076 | Legend of Blue Eyes White Dragon | 076 | Common | €0.06 |
| M-Warrior #2Legend of Blue Eyes White Dragon · 077 | Legend of Blue Eyes White Dragon | 077 | Common | €0.02 |
| M-X-Saber InvokerOrder of Chaos · 099 | Order of Chaos | 099 | Secret Rare | €1.22 |
| My Body as a ShieldMagician's Force · 092 | Magician's Force | 092 | Common | €1.52 |
| My Friend PurrelyAmazing Defenders · 020 | Amazing Defenders | 020 | Ultra Rare | €0.15 |
| Myriaday DragonBeyond the Brave · 035 | Beyond the Brave | 035 | Common | €0.04 |
| Mysterion the Dragon CrownLightning Overdrive · 034 | Lightning Overdrive | 034 | Ultra Rare | €0.08 |
| Mysterious GuardLegacy of Darkness · 021 | Legacy of Darkness | 021 | Common | €0.02 |
| Mysterious PuppeteerStarter Deck: Kaiba · 043 | Starter Deck: Kaiba | 043 | Common | €0.08 |