For many Yu-Gi-Oh! Master Duel players, spell cards are considered the strongest or second strongest card type in the game. Unlike other card games, Yu-Gi-Oh! doesn't have a resource system for activating cards. Players can activate any number of spell cards they want per turn, assuming they meet the card's activation requirements.
This fact coupled with how strong a single spell effect can be makes the inclusion of specifically strong spell cards a must in pretty much any deck that can run them. How strong or useful a spell card is will oftentimes be determined by the current metagame or format being played. What decks are the most powerful, and which effects do the best job countering those decks?
10 Crossout Designator
Crossout Designator is a quick-play spell card that has a really powerful effect. This card allows its user to banish one card from their deck and if they do, that card's effects are negated until the end of the turn.
This card is mostly used as a means of countering popular hand traps like Ash Blossom & Joyous Spring and Infinite Impermanence. The only thing holding this card back is the fact that the user needs to be playing a copy of the hand trap they're responding to in their deck.
9 Chicken Game
Chicken Game is a powerful field spell that allows the turn player to pay 1000 life points during the main phase to either draw one card, destroy Chicken Game, or have their opponent gain 1000 life points.
This card can be used as a draw engine in any deck that uses field spells or that has a way to destroy a card on the field for cost in order to activate a different effect. This card also has the added benefit of preventing the player with the lowest life points from taking damage, so it's perfect for decks that want to stall out or play the long game.
8 Forbidden Droplet
Forbidden Droplet is a quick-play spell card that has the following effect: The user sends cards from their hand or field to the graveyard, then they select monsters on the opponent's side of the field up to the number of cards sent to the graveyard by this effect, those monsters have their effects negated and their attack points halved until the end of the turn.
The opponent cannot respond to this card's effect with card types that were sent to the graveyard with this card's effect. Forbidden Droplet is a bit confusing but it's one of the best going second cards in the game, and because it's a quick-play spell it can be activated during the opponent's turn.
7 Pot of Extravagance
Pot of Extravagance is a normal spell card that allows its user to banish 3 or 6 cards from their extra deck face down, then they can draw either 1 or 2 cards respectively. The user must use this card at the start of the main phase and cannot draw cards with other card effects for the rest of the turn.
This card is a great consistency booster for any deck that doesn't need its extra deck or decks that make very little use of it.
6 Harpie's Feather Duster
Harpie's Feather Duster is a normal spell card that has a very simple effect: Destroy all Spell and Trap Cards the opponent controls. Short, sweet, and very powerful. This card is so powerful that it is currently limited to one copy per deck
Harpie's Feather Duster is great for going second and getting rid of the opponent's problem back row cards like Solemn Judgment and Forbidden Droplet, or even floodgates like Skill Drain and Summon Limit.
5 Lightning Storm
Lightning Storm is a normal spell card that has the effect to destroy all face-up attack position monsters the opponent controls or destroying all spell and trap cards the opponent controls. This card is another fantastic going second card.
The only downside is that Lightning Storm's effect cannot activate if the user controls any face-up cards on their side of the field. Lightning Storm is great turn 2 but not very good turn 1 since it isn't a quick-play spell.
4 Super Polymerization
Super Polymerization or Super Poly for short is another fantastic quick-play card. This card allows its user to fusion summon a fusion monster from their extra deck using cards on either side of the field as material. This effect cannot be responded to either so it is the perfect card for breaking really scary boards of monsters since most boss monsters aren't immune to being tributed.
This card is great for going first or second, the only downside it has is the user needs to build their deck and extra deck around Super Polymerization, and even then sometimes Super Polymerization won't have any targets it can make with its effect.
3 Cosmic Cyclone
Cosmic Cyclone is a quick-play spell with a very simple yet powerful effect: Pay 1000 LP, then target 1 Spell/Trap on the field; banish it. This card provides the best form of spell and trap removal through banishment. A good number of archetypal spells and traps have effects that trigger when they are destroyed or sent to the graveyard.
Cosmic Cyclone prevents those effects from triggering since they are banished instead of being destroyed. This card is also quick-play, so it can be used on the user's turn or their opponent's turn if it was set the turn prior.
2 Called by the Grave
Called by the Grave is a quick-play spell card that banishes one card from the opponent's graveyard, then it negates the effects of that banished monster for the rest of the turn. This spell is excellent for dealing with hand traps, as long as they are monster cards.
It can also be used to disable a key part of the opponent's combo, assuming that combo involves activating a monster effect in the graveyard. Called by the Grave is so good that it has been placed on the semi-limited list, meaning players can only have 2 copies of this card in their deck.
1 Upstart Goblin
Upstart Goblin is a normal spell card with the simple effect of allowing the user to draw one card, then their opponent gains 1000 life points. What makes this effect so powerful is its simplicity. It isn't once per turn and it doesn't have any restrictions. Upstart Goblin can be played at three copies, effectively reducing the user's deck size from 40 to 37.
This allows the user to thin their deck and get to their combo pieces more consistently. Pretty much any deck in Master Duel can play Upstart Goblin and benefit from the slight consistency boost it provides. Just watch out for those Ash Blossom & Joyous Springs.
Yu-Gi-Oh! Master Duel is available on PC, PlayStation 4, Xbox One, PlayStation 5, Xbox Series X/S, Nintendo Switch, Android, and iOS.