Most of the time, the only rules that apply are how much energy is needed to perform an attack and how many cards of a certain type can be used on one turn
Jidoor, Aristocratic Capital has an ability that mills half a players library tacked to an adventure, and if you have some ways to return lands from the battlefield to your hand, you can make a pretty good combo (Fear of Isolation, Kor Skyfisher)
How many Pack Points does it cost to craft Shroomish
(This Digimon checks 1 fewer security cards.) If this card was played by [Trial of the Four Great Dragons]'s effect, all of your opponent's Digimon gain Security Attack -2 until the end of your opponent's turn instead
While it generates less cards during the combo, it also requires less cards
But, despite such a low price, this card will be a great helper on the battlefield