| Moment's Peace | 1466★ |
| Molten Collapse (2 variants) | 2677 |
| Moldervine Reclamation (2 variants) | 1716 |
| Mogis, God of Slaughter | 78 |
| Mogis, God of Slaughter (2 variants) | 9994 |
| Moggcatcher | 7081 |
| Mogg War Marshal (2 variants) | 1618 |
| Mogg Assassin (2 variants) | 2517 |
| Mizzium Mortars (4 variants) | 2249 |
| Mitotic Slime (2 variants) | 2815 |
| Mistbind Clique | 116 |
| Mishra's Bauble | 2046 |
| Mishra's Bauble (2 variants) | 2041 |
| Misdirection | 1272 |
| Miscast | 2332 |
| Miscast (2 variants) | 2317 |
| Mirror of Galadriel (2 variants) | 1295 |
| Mirror Entity (2 variants) | 2514 |
| Mirri, Weatherlight Duelist | 26 |
| Mirkwood Bats (2 variants) | 2565 |
| Miren, the Moaning Well | 7108 |
| Mirage Mirror (2 variants) | 2030 |
| Mirage Mirror | 7025 |
| Minsc & Boo, Timeless Heroes | 879 |
| Minds Aglow (2 variants) | 7028 |
| Mindcrank (2 variants) | 2186 |
| Mindcrank (2 variants) | 2456 |
| Mind's Eye (2 variants) | 2704 |
| Mind's Dilation (2 variants) | 1180 |
| Mind Flayer, the Shadow (2 variants) | 340 |
| Mina and Denn, Wildborn | 1270 |
| Miles "Tails" Prower (2 variants) | 2085 |
| Mike, the Dungeon Master (2 variants) | 346 |
| Mikaeus, the Unhallowed (2 variants) | 490 |
| Mikaeus, the Unhallowed | 846 |
| Miirym, Sentinel Wyrm (2 variants) | 2500 |
| Might Sliver | 652 |
| Midnight Reaper (2 variants) | 1171 |
| Midnight Clock (2 variants) | 2217 |
| Michonne, Ruthless Survivor | 146 |
| Michiko Konda, Truth Seeker (2 variants) | 259 |
| Meteor Golem (2 variants) | 1660 |
| Meteor Golem (2 variants) | 2225 |
| Meteor Golem (2 variants) | 285 |
| Metamorphose | 2155 |
| Metalwork Colossus (2 variants) | 377 |
| Metalwork Colossus (2 variants) | 378 |
| Metallic Mimic (2 variants) | 194 |
| Mesmeric Sliver | 620 |
| Mesmeric Orb (2 variants) | 2457 |