How to grind foils for packs in the second part of the game
This is a technically a spoiler for the second part of the game. I suggest that you leave the cabin before looking at this guide.
If you picked the undead starter pack this will be pretty easy, otherwise you will need to pick up a few cards to do this first.
Have at least one skeleton, three grave diggers, and one bone heap. This is what i found at the beginning, there might be a better method that i haven’t seen yet. After you have these cards go to the second floor of the mage tower and battle the training dummy. In this fight you can simply place one skeleton to gain a bone, then use grave diggers to build up a large amount of bones to buff your bone heap. I suggest getting the training dummy to one hit from death,with other skeletons since they die at the end of your turn, and then going in with the heap with around 30 bones to buff it. Since you gain foils from excess damage dealt at the end of the fight you can get a few packs from one encounter, and since this is a repeatable fight you can receive enough to gain a few packs per fight.