Check my guide on the achievement
"I DID ENGOLDENATION" To unlock this achievement you will need to Engoldenate all 50 cards in your card collection. The quickest way I found to do this was to play the shortest song "Taps" with Turbo mode enabled and Auto toot enabled in the accessibility settings. It took me around an hour to get every card using this method.
The song will be 21 seconds long with Turbo mode enabled and you will earn around 500 toots per go or around 1800 if you can perfect the song. Its hard to say how many toots you would need to earn to unlock every card from opening sacks but I would recommend getting to 10000 toots and opening 20 sacks.
Once you do this 3 times you should have a decent collection, engoldenate any cards with 10 or more duplicates by clicking on the card and then the "Engoldenate" button. The card will now have a golden border and any other duplicates you may gain can be turned to turds by clicking the "Turd Card" button and the "All duplicates" button. The turds are a currency to build any cards you don't have, it will cost 399 turds to build one card. Build the required amount of cards to get a selected card to 10 and perform Engoldenation.
Make sure not to turd any engoldenated cards or else you will have to earn it again.
The achievement will popup after you engoldenate the last card.