In Yu-Gi-Oh!, the term hand trap refers to cards that can be activated from the hand in order to interact with the opponent during the opponent's turn. These cards are not limited to only being trap cards, in fact, most hand traps tend to be monster cards.
There are multiple different hand traps available in Yu-Gi-Oh! Master Duel and each one requires specific conditions to be met before they can be activated. As a result, the viability of each hand trap is dependent upon the current meta the game is in. In general, most decks that are comparatively viable will incorporate at least a couple of hand traps into their deck list.
10 Droll & Lock Bird
Droll & Lock Bird is a level 1 wind spellcaster-type effect monster. This card's effect can be triggered when the opponent adds a card from the deck to the hand, except for cards drawn during the draw phase.
The owner of this card can send it to the graveyard as a quick effect in order to prevent their opponent from adding cards from their deck to the hand for the rest of the turn. How good Droll & Lock Bird performs greatly depends on the current meta, as there are plenty of decks in Yu-Gi-Oh! that don't add cards to the hand but instead, banish them or send them to the graveyard.
9 Artifact Lancea
Artifact Lancea is a level 5 light fairy-type effect monster. This card's effect can be triggered at any time during the opponent's turn while this card is in the hand or face-up on the field. The user can tribute this card; for the rest of the turn, neither player can banish cards for the rest of the turn.
This card can also be set in the spell and trap zone and if it's destroyed by the opponent during their turn, the controller of this card can special summon this card to the field.
8 Evenly Matched
Evenly Matched is one of the few hand traps in the game that is an actual trap card. This card's effect can only be activated at the end of the battle phase; the opponent banishes cards from their field until they control the same number of cards the owner of this card controls. If the user controls no card, this effect can be activated from the hand.
This effect is really strong because it gives the user an out to their opponent's entire board excluding one card, with the only cost being the user's battle phase that turn. Getting the effect off can be a bit tricky and requires the user to play around with any negates their opponent has on their field.
7 PSY-Framegear Gamma
PSY-Framegear Gamma is a level 2 light psychic-type tuner monster with the following effect: if the opponent activates a monster effect while this card's owner controls no monsters, special summon this card from the hand to the field, then special summon one "PSY-Frame Driver" from your hand, Deck, or GY, then negate the effect of that opponent's monster and destroy it.
PSY-Framegear Gamma's effect may be a mouth full but it is a really strong effect. This card can't be normally summoned or set so the only way to get it out on the field is by its own effect. Luckily, its effect is universally good and gives its user two monsters that can be used for synchro or link plays.
6 Ghost Ogre & Snow Rabbit
Ghost Ogre & Snow Rabbit is a level 3 light psychic-type tuner monster. This card's effect can be activated when a card that was already face-up on the field activates its effect. When this happens, the user can discard this card and if they do, the card that activated its effect is destroyed.
Ghost Ogre & Snow Rabbit's effect does not negate the effect of the card it destroys, but it's still very useful for getting rid of monsters the opponent controls that could be used for extra deck plays and stopping continuous spell and trap cards.
5 Nibiru, The Primal Being
Nibiru, the Primal Being is a level 11 light rock-type effect monster. This card's effect can be triggered after the opponent has normal or special summoned 5 times in one turn. If they have, the controller of this card can tribute as many face-up monsters on the field as possible, then Nibiru, the Primal Being is special summoned from the user's hand to the user's side of the field.
After that, a token is summoned to the opponent's field that has the attack and defense of all monsters' tribute by this effect combined. Nibiru is the ultimate form of monster removal card because only a few monsters in the game have immunity to being tributed and will often leave an opponent with little to no plays left to make for the rest of their turn.
4 Ghost Belle & Haunted Mansion
Ghost Belle & Haunted Mansion is a level 3 earth zombie-type tuner monster with the following effect: when an effect is activated that would either add a card(s) from the graveyard to the hand, deck, and/or extra deck, special summon a monster or monsters from the graveyard or banish a card from the graveyard. Players can discard Ghost Belle & Haunted Mansion from their hand in order to negate that activated effect.
With how popular it is for decks to special summon from the graveyard or banish cards from the graveyard, Ghost Belle & Haunted Mansion finds itself a much more popular pick than it used to be.
3 Infinite Impermanence
Infinite Impermanence is another of the few trap cards in the game that is also a hand trap. Infinite Impermanence has the effect that allows the user to target a monster on the opponent's side of the field and negate its effect.
If Infinite Impermanence was set on the field when this effect is activated, negate all spell and trap cards in the same column that Infinite Impermanence was in. If the user of this card doesn't control any other cards on the field, this card's effect can be activated from the hand.
2 Ash Blossom & Joyous Spring
Ash Blossom & Joyous Spring is a level 3 fire attribute zombie-type tuner monster. Ash Blossom & Joyous Spring, or just Ash for short, is one of the most popular hand traps in all of Yu-Gi-Oh!'s history. It is a staple card in pretty much every deck that can run it and for good reason.
Ash has the effect to negate the activation of a card that includes the following effects: add a card from the deck to the hand, special summon a monster from the deck, and send a card from the deck to the graveyard. This card basically stops the opponent from using an effect that searches a card out from the deck, and considering how universal those kinds of effects are to good deck building, it's no surprise Ash is as popular as it is.
1 Maxx "C"
Maxx "C" is a level 2 earth insect-type effect monster with a very simple yet powerful effect. When this effect is activated, discard Maxx "C" to the graveyard, for the rest of the turn, every time the opponent special summons a monster to their field the user of Maxx "C" draws 1 card.
This effect essentially allows its user to dig through their deck for more hand traps or just have more resources than their opponent can deal with. More often than not, when a player activates Maxx "C" their opponent usually ends their turn shortly after. Maxx "C" is so powerful that it has been banned in the TCG for many years and can win players the game if its effect actually resolves.
Yu-Gi-Oh! Master Duel is available on PC, PlayStation 4, Xbox One, PlayStation 5, Xbox Series X/S, Nintendo Switch, Android, and iOS.