Hi there! You would not believe it but I only pulled one gold foil legendary card in 1 year of opening booster packs- like 200-400 packs a week at times when I was only building my maxed set way back then that was the only way to. Yet, I have used the brilliant potions for gold and legendary both together on my orb packs and pulled 2 Gold Foil Legendary cards! It is not a guarantee at all but I think the odds are pretty good when you get the 100 orb pack + 10 free- I am going to get another 100 and more brilliant potions and then I will let you know how I do! :-)