One Time Fling
This is one of, if not the only, HERO monster that never made the jump to Master Duel
Elemental HERO Air Neos
Spell-storing Cave
Mystic Mine
Light and Darkness Dragon/Amorphage Sloth
Dragon Type
Beatunaful Princess, Mermail Abyssteus, Star Eater
Mermail Abyssteus
This card first appeared in the OCG in Clash of Rebellions, but, controversially, existed in the TCG only as a prize card until its reprint in the first Battles of Legend.
Minvera, the Exalted Lightsworn
Eagle Shark, Blizzard Shark, Mermaid Shark
Blizzard Shark
One of the most infamous boss monsters in the game, this monster has lent its name to every card like it: a giant monster unaffected by everything.
Apoqliphort Towers
Chaos Soldier, the Chaos Warrior
Black Luster Soldier - Soldier of Chaos
Neo-Spacian Glow Moss/Mokey Mokey
Instant Fusion, Future Fusion, Miracle Fusion
Miracle Fusion
This machine monster first found its place in the meta in ABC, which used it to climb to Cyber Dragon Infinity.
Galaxy Soldier
Volcanic Blaster, Volcanic Hammerer, Volcanic Cannon
In Edison Format, Debris Dragon would be a mediocre card at best were it not for this monster's existence, which gives Debris Dragon a lower-level monster to climb to with Ryko.
Iron Chain Dragon
Angel Knight Perseus
Airknight Parshath
Agido, the Ancient Sentinel/Necro Gardna
1300 DEF
Snowman Eater
First appearing in Duelist Alliance in the OCG, the TCG would not get this card until 2015 in a side set. It would be another 4 years before this card finally found its place in the meta, as the most powerful boss monster of the format.
Number 86: Heroic Champion Rhongomyniad
Satellarnova Burst, Satellarknight Skybridge, Stellarnova Wave
Satellarnova Burst
You can think of this card, released in Tactical Evolution, as the original Mask Change, for one of the worst archetypes in the game.
NEX
Demonic Water Deity - Suga
Suijin
Subterror Fiendess/Crusadia Reclusia
Spellcaster
Stardust Charge Warrior, Crystal Wing Synchro Dragon, D/D Lamia
Stardust Charge Warrior
Burning Abyss used this Xyz monster to help their matchup against Kozmo
Number F0: Utopic Future
Mist Valley Scout, Mist Valley Watcher, Mist Valley Executor
Mist Valley Scout
Scrap Raptor made Scrap Chimera expensive before its reprint, but this spell, the one that searches Scrap Raptor, still has not received one after 12 years.
Scrapyard
Magical Crown - Missing Sword
(Hint: This is a Number monster. You do not need the number)
Number 74: Master of Blades
Turbo Synchron/Battlewasp - Sting the Poison
Reasoning, Kycoo the Ghost Destroyer, Reinforcement of the Army
Kycoo the Ghost Destroyer
The win con for budget players from one of the most budget-friendly structure decks of ARC-V, the OCG received this spell card in Crossed Souls as a common.
Domain of the True Monarch
Koa'ki Meiru Ice, Koa'ki Meiru Ghoulungulate , Koa'ki Meiru Dragon
Koa'ki Meiru Dragon