Take part in events The easiest way to get Promo Cards is by participating in the games events
Just having Inti around means that it gets stronger each turn when attacking, and you have a baseline 2/2 that already attacks as a 3/3, not to mention synergies with unblockable creatures or big, fatty green creatures
The problem here is the current environment for collecting in 2021, as smpratte mentioned, nowadays is just too volatile, speculators, hypedriven, etc
This makes your dorks have a power and toughness of 6/6 great for Green and then they are Oozes too
For example, Liliana of the Veil isnt on this list, but youll see a very accurate Liliana forgery further down in this article
Go on TCGplayer or Misprint and just buy cards of Pokemon you like