None, once you beat an Set amount you get some. But none give you X amount over and over again if you keep doing it. So it is best to do them all
All quests have a slight chance of dropping nobility or health crystals, even after mastery. Nobility are uncommon, Health Crystals are very rare.
Cons - Hard to earn gold and grow Youre open to attack as long as you have gold out Easy to pin Pros: Cant be hit with no gold so good if you like sleep Dont need pots, so once BC its quite fun and cheap.
You can buy them from the market place for 39 nobility points (might be more or less). They also come off of drops from certain EBs.