Abyss Dryspring is the fastest dungeon you can farm for a Golden bunny. You can do it in about 5 minutes solo with the right equip. My char with medium lvl equips finishes this in 7 minutes which is a pretty good time. I started farming at 32 and have gotten 5 golden bunny.
Golden Bunny drop Premium Epic Heraldry which you can sell for a lot of gold. Farming in abyss also provides you with gifts, epic enhance codes, fragments of dimensional gem and a higher chance for Royal chest.
*Note to SEA players - try to keep the Epic enhance codes for warriors to sell. It only needs 2 binding stamp(only use incomplete) and if you're lucky you get to seal it on your first try. Warrior items sell highly with the Epic Crystal code at about 150 gold per piece.
Credits: CrownPoidaa