Dang, I'm so unlucky.
You open two packs and get a gold foil. I opened 21, and got only 1 legendary and 4 epics. No gold foils in over 100 cards:(
I had 6 charges of both potions and they didn't help at all, the legendary coming near the end.

I like both the serpentine spy and the cave slug because they have 2 attack (at level 1) to get stuff done.
I like cave slug because it has more health than most cards, and serpentine spy because it is fast.