Field Day
If your opponent has more monsters than you do on the field, they cannot activate monster effects or attack, but if you control more monsters, you cannot do so.
Mystic Mine (Thanks Jeff Leonard)
This deck is one of three competitively viable Ritual Decks that were meta at different points. Using its main deck monsters to gain advantage with the "Tribute Benten" loop, this deck ritual summons using ATK values instead of levels.
Drytron
An iconic deck used by Duel Monsters' Seto Kaiba, this legendary engine of destruction was nearly invincible in 2016, so much that its opponents in the world championship of that year did not live to tell the tale of victory.
Blue-Eyes
Jeff Leonard popularized this Valkyrie spell thanks to his deck focused around "Mystic Mine". It is able to stack the top few cards of your opponent's deck
Goddess Skuld's Oracle
An FTK starring Substitoad and Mass Driver, this deck would use Substitoad to bring its archetype out multiple times, and Mass Driver could deal lethal damage, as neither one of its monsters nor itself are once per turn. Substitoad and Mass Driver are currently still Forbidden because of how consistently powerful at FTKing and control matches this deck was.
Frog FTK
A Field Spell that can search Polymerization and add back a Fusion Material in the End Phase
Fusion Recycling Plant
This iconic monster used by Yugi does indeed have its own archetype. It is searchable off of Gateway to Chaos
Black Luster Soldier
A series of monsters who can tribute summon themselves by tributing Spells and Traps instead of monsters and spells and traps that have decent graveyard effects. Their Field Spell is also played in Dinosaur decks, as it requires you to destroy a card in hand as cost to search a card from one of two archetypes, and Babycerasaurus loves destructuction.
True Draco
Debuting in 2008 in the Gladiator's Assault set, this Trap card was used by Gladiator Beast decks to stop Dark Armed Dragon decks from activating their effects. It has a Light counterpart in the same set..
Shadow Imprisoning Mirror
Kind of a janky FTK utilizing Earthbound Immortal Aslla Piscu and Union Carrier, this deck focused on spamming tokens to your opponent's field with Black Garden, as well as Rokket Tracer to destroy the Immortal and deal damage, bringing out another member of its archetype for Borrelsword Dragon to target, destroy, and burn. It is much better played as a deck that builds unbreakable boards with the currently hindered Guardragon engine, possibly with Dragunity and Chaos cards
Dragon Link FTK
This Field Spell is considered one of the best, as it keeps cards from leaving the graveyard, and it gives an attack boost to its home archetype
Necrovalley
Released in 2020, this Ritual archetype could ritual summon WITHOUT a Ritual Spell, and could do so on your opponent's turn. It sure misses Block Dragon
Megalith
This deck full of Link-1s and a bunch of Spell Cards was first popularized in 2018, but also played a vital role in TOSS format. Given you had no monsters in the Main Monster Zone and 3+ spells in the GY, their Spells could gain bonus effects.
Sky Striker
This card saw some niche play in certain decks that need to clear spell and trap zones or get spells and traps to the graveyard for its ability to send a Spell or Trap in Hand alongside itself to remove a card on the field, and its grave effect to send a Spell/Trap to the GY to add itself and special summon a Zombie monster. It's a bonus monster for your backrow troubles
Eldlich the Golden Lord
Most famous for a showcase in 2018, when Jesse Kotton piloted this very skill intensive FTK and wiped out an unsuspecting kid in a 2-0 fashion. It utilizes cards that can gain advantage when discarded and a fairly sizeable discarding engine that can also be an draw upon summon. It is a unique FTK in the fact that it can utilize Beginning of the End due to everything being dark
Danger! Dark World FTK
Given it is activated on a turn where your opponent's field is larger than yours, this card can act as a pseudo- Soul Charge, for its home archetype, but it normally is used to summon two of its home archetype from the hand. It also can be directly searched by a Link monster.
Boot Sector Launch.
Having its main card come out as early as Magic Ruler and one of its bosses banned thanks to Metamorphosis in 2005, this deck specializes in one thing and one thing only: Stealing monsters
Relinquished
This deck was famous for its role in 2019's "TOSS" format. It was known as the format's "Jack of all trades", and has a Fusion Spell that can act as a pseudo- Super Polymerization given the right circumstances, and is the reason Lady Debug was limited at one point.
Salamangreat
This Dragon, similar to a Mekk-Knight, can special summon itself if 3 cards are in the same column, destroy all cards in its column, and block all other zones in said column. If you have an Artifact Scythe set in your S/T zone, you can trigger it on your opponent's turn, as an Artifact would do so if it is destroyed, but also giving you an Extra Deck lock for a turn due to Scythe's effect.
Iron Dragon Tiamaton
Due to a certain Winged Beast that can be summoned from Instant Fusion and how easily the soft Once Per Turn that is Supreme King Dragon Starving Venom was to summon, this FTK was possible by using two Starving Venoms to burn for lethal damage. They did not ban the burn card, they banned Starving Venom for this.
Pendulum FTK
This Field Spell was the center of a deck that came out of nowhere in 2017.This field spell was a ruling nightmare for Judges, and it is treated as "Umi" and can search "Phantasm Spiral Battle"
Pacifis the Phantasm City
A Hidden Arsenal Archetype that could (and still can) cause a loop that, while somewhat inconsistent, could rip away your opponent's whole hand. It is one of the warring tribes in Duel Terminal 2 lore.
Gishki
In 2014, this deck was very powerful due to being able to stack itself and utilize a built-in card similar to Graceful Charity. Soul Charge was this deck's best friend, and you might see Lonefire Blossom in this deck
Sylvan
This Zombie monster that detaches a material from an xyz monster to special summon a Zombie from the GY was directly responsible for one of the most consistent viable FTKs in 2015 that could become a hand loop at will, but the loop was one of the longest combos in the history of Yugioh.
Blue-Blooded Oni
An FTK starring an iconic monster from the DM anime, this deck uses its at home fusion spell and burn card with Serial Spell to do lethal damage. Do NOT play this FTK, it is EXTREMELY inconsistent
Red-Eyes FTK