Pot of Greed was first released in the TCG in 2002, as apart of “Legend of the Blue-Eyes White Dragon”. However, the card was banned on the game’s October 2005 banlist, and has remained forbidden ever since. This brings up the question “Why is Pot of Greed banned?”
Simple effect, Big rewards
Hand advantage and obtaining combo pieces have been a part of Yugioh since the game first introduced combos. For this reason, competitive Yugioh decks are almost always at the minimum of 40 cards. Fewer cards mean more consistency. If given the opportunity some decks would run even fewer cards in order to get combos out quicker. This where Pot of Greed comes in.
Pot of Greed allows the player to draw 2 cards, and this essentially gives the player the ability to have a plus one in hand size as well as a chance to obtain the critical parts of their deck. This essentially makes your deck 37 cards, as you will automatically play this card in order to replace it in hand. Upstart Goblin only you draw one, and it was good enough to be limited.
No tradeoffs or risks
Plenty of cards throughout the history of Yugioh have given players the ability to draw cards, but most of them have some kind of tradeoff or risk involved. The problem with the card is that it has no downside, and the player only gains a significant advantage by playing it. Draw 2 cards is just too good.
The game of Yugioh needs some kind of balance in order to make the game fair for both players. This normally comes in the form of a trade-off. In order to get advantage, you typically need to have some kind of risk whether this is taking life points or discarding. Pot of Greed has no downside to play.
Can Pot of Greed be unbanned?
Probably not. The card has been a mainstay of the ban list, and if Konami wanted it unbanned it would have happened. The card just gives too much advantage in its current state. Also, the card has been reimagined so many times that it is unneeded.
If you want to learn more cards that allow you to draw more cards may I recommend this article on Graceful Charity?