Burn Baby, Burn
Volcanic Scattershot
Seen at the brickfest of the finals of the 2016 world championships, this monster finally got the support it needed thanks to Konami printing a card that countered the entire meta game for it.
Blue-Eyes White Dragon
Used in Dragon Link, this monster allowed you to easily go into level 8 or 9 synchros on its normal summon and tuner subtype.
Rokket Synchron
Blue-Eyes White Dragon, Gizmek Orochi the Serpinton Sky Slasher, Dogmatika Maximus
Level 8
This is a shuffling method where duelists section their cards into different stacks, most commonly 8.
Pile Shuffling
Erratad for it's ability to create draws, this card's neutered form would still see itself placed on the banlist as far into Zoodiac format.
Ring of Destruction
This 1550 attack monster is the strongest non-tribute normal summon in LOB format.
Skull Red Bird
Played primarily as a removal option, this card allows you to get around monsters that have both destruction and targeting protection, assuming you brought back the right monster.
Winged Dragon of Ra - Sphere Mode, Odd-Eyes Revolution Dragon, Divine Serpent Geh
All monsters with ? attack.
Don't get caught doing this sleight of hand technique, where you will a card to the top of your deck.
Stacking
One of the world's worst FTK enablers, this Red-Eyes card is also the name of it's titular monster's attack in the anime.
Inferno Fire Blast
This particular technically-a-bird is part of the archetype Sir Emanon is using in the upcoming Remote Duel YCS, having only one printing as a McDonalds promo.
Flying Penguin
Light and Darkness Dragon
Neo-Spacian Glow Moss, Nekroz of Valkyrus, Numeron Wall
Ending the Battle Phase
Players will often do this to their cards after a loss, also described as a term of one surrendering.
Scooping
This dark machine was eventually erratad due to its insane OTK and even FTK potential, with the ability to inflict repeated, non OPT burns.
Dark Strike Fighter
Serpent Night Dragon
Part of the infamous Chick the Yellow OTK, this card would be repeatedly bounced back and re-activated due to the prior activation of a Makyura the Destructor.
Call of the Haunted
Elemental HERO Stratos, Dragonpit Magician, Ally of Justice Decisive Armor
Cards that Destroy Spells / Traps
This practice of card protection was banned in the TCG for years out of fear of dishonest play until relatively recently, where it became legal to do so.
Double Sleeving
Played in zoodiac lists high on copium, this train card allowed you to gain repeated pops when ranking up.
Barrage Blast
Gamers, rise up. For we are a minority whos treatment are akin to this monster.
Oppressed People
Used in handloop variants of Copium World, this monster allowed for repeated synchro summons due to it being technically infinite material, most commonly used for XX-Saber Gottoms.
Beast of the Pharaoh
Harpie's Feather Duster, Torrential Tribute, Thunder Dragon
Cards that are Specifically Searchable
Be warry of this southern asian shuffling technique, as it can easily lead to card and deck manipulation.
Hindu Shuffling