Pot of Avarice

To tell you the truth, not many deck can fit 2 to 3 copies of this card. as it will just be a dead draw if you don't have at least 5 monster cards in your grave. if you include just 1 copy, it might serve your deck well as you can recycle 5 monsters back to your deck and draw 2 cards. So, why is this card limited?

This card can also be a draw power for Lightsworn deck as they self mill quite fast, so most of your monster will be in your grave, but a normal Lightsworn user wouldn't return all Lightsworn monster that was milled as it will become ineffective. But still, 3 copies of Pot of Avarice can help with the draw power of an aggressive self mill Lightsworn deck.

Also, due to some monster effects that can special summon another monster from deck such as Giant Rat, Mystic Tomato, Nova Summoner, Gusto Gulldo, Gusto Egul etc. In addition to the infamous new Reborn Tengu as it has become very popular. A lv 4 1800 power house with ability to special summon another Reborn Tengu from deck when it is removed from the field. Could be destroyed by battle or card effects, removed by Dimensional Prison, return by Compulsory Evacuation Device or sent to grave for synchro or tribute.

Including the popular Rescue Rabbit as it removed it self to special summon 2 normal monster of the same name from your deck and use it for xyz summon. in case if the xyz monster is destroyed, you have at least 3 monster in your grave.

This shown  that it is very easy to set several monsters to the grave, and using Pot of Avarice to recycle them over is definitely be very helpful as it also provide draw power. Since that sending monsters to grave is actually quite easy for current meta game, this card become almost as outstanding as the infamous Pot of Greed.