I was toying with the idea of a Warlock quest variant.
Each character starts with 3 warlock quests. With completion of three you are teleported to the Warlocks cave to get a Talisman and then pull three more cards.
With the second cash in of the warlocks quest you can gain a treasure from the dungeon stack. You can gain additional quest cards to make completion of the quest easier. No limit on how many quests you have at once.
I've been doing some testing with it and it seems kind of neat. Though it makes one spell useless - path of destiny.
I was also thinking of making quests that discard, you must discard the object at the warlocks cave.
I think some of the variants in the rules are a little too powerful - treasure rewards variant (frostmarch).
Let me know what you think of this idea.
Maybe I should call it the"Warlock Prophecy Quest"