- Majestic Dragon
- Majestic Jester
- Majestic Red Dragon
- Majestic Star Dragon
- Makyura the Destructor
- Malice Doll of Demise
- Mammoth Graveyard
- Man-Eater Bug
- Man-Eating Plant
- Manju of the Ten Thousand Hands
- Marauding Captain
- Marie the Fallen One
- Marshmallon
- Masaki the Legendary Swordsman
- Masked Beast Des Gardius
- Masked Dragon
- Masked Knight LV3
- Masked Knight LV5
- Masked Knight LV7
- Master Kyonshee
- Master of Oz
- Master of the Flaming Dragonswords
- Maternal Junk
- Mathematician