The 11 most feared yugioh monster effect cards ever.

Valkyrion The Magna Warrior - This card is hard to put together in the game. You have to summon 3 cards at the same time dueling against your opponent.

Buster Blader - If you have dragons it does not work but if your opponent have dragon types on his side of the field well that is a very big if.

Barrel Dragon - You get to toss a coin 3 times. If 2 out of 3 results are heads destroy 1 monster on your opponent's side of the field. This effect is done once per turn and during your turn. In real life it will get a lot of confusion for you and your opponent to play this card is not always much simple to play because it will lead a big mess in the end of each turn.

Jinzo - This card can be a lot tough to beat in the game with out using any trap cards.

Insect Queen - This type of card come from the Game boy advance games I play in the past. It is not a real card it can be a challenge to beat to play it in the game and the real game if it is already made in real life.

Shadow Ghoul -  The bad news about this card when use in the duel it can be a lot problem against you. The good news is that you have time from stopping this card from summon it in the field.

Exodia the Forbidden One - To end the game and win the duel if summon with the parts in the deck. It is A very will know card in the game.

Cyber - Stein - It can be a big problem if your opponent can summon the highest attacking monster from your Fusion monster deck. Like Blue- eyes Ultimate Dragon on the field. The good news the card it self has A low ATK points and if you hit that monster right it is a more likely to win the duel.

Muka Muka - Increase the ATK points in your hand. If you can use the the magic card name Infinite Cards at the right moment the person do not know how far this monster will go in ATK points

Time Wizard - A 50 / 50  chance to win. That is a big risk to play if you are crazy.

Copycat - If you have a high attacking monster on the Field you can copycat it that ATK points. Then use another magic or trap card to destroy the real monster in play to get to the life points.

If you can do better try making a list of Yu- Gi-Oh cards that make you worry on the duels you played in the game that your opponents can use against you that you are fear of.