Based on impact and discussion:
* Pot of Greed: This simple but powerful card lets you draw two extra cards, which is incredibly valuable in any deck. It was banned for its sheer power and potential for abuse.
* Raigeki: This card wipes out all your opponent's monsters, leaving them vulnerable. It's considered a powerful and impactful card, and its ban helped slow down the pace of the game.
* Sangan: This card is a powerful search engine that can easily access any other monster card in your deck. It was banned for its ability to easily get powerful monsters onto the field.
Based on nostalgia and recognition:
* Graceful Charity: Another card that lets you draw extra cards, this one is highly sought after by collectors and nostalgic players.
* Change of Heart: This card lets you take control of your opponent's monster, making it a very powerful and unpredictable card.
* Premature Burial: This card could bring back a monster from the graveyard, offering powerful recovery options.
It's important to note:
* Forbidden cards are banned for a reason. Their presence in the game would create an unbalanced playing field, making it unfair for others to play.
* Popularity can change over time. New cards and strategies can emerge that make previously banned cards less relevant, or even increase their desirability.
Ultimately, the "most popular" forbidden cards are those that have left a lasting impact on the game, whether for their power, their history, or their potential for abuse.