Some of the more popular ones are Waterworks, Shan-To-Kor, Tangle-root, and Delera's
Depths Series Quest Guide Category Quest - When trying to level your lowbies (low-level characters); you tend to do quest series to get the most rs gold XP possible. Some of the more popular ones are Waterworks, Shan-To-Kor, Tangle-root, and Delera's.
There's another quest series over at House Deneith known as the "Depths Quest". The series consists of four related but independent quests. This means that you can choose to do them all in one go, or do one and come back for the other quests on the next day.
In fact, you can start at any point without having to worry about not being able to advance to the next. You can get the quests inside the Hammersmith's Inn.
PREPARATION - The usual start off point is "Depths of Despair". The quest entrance is just next to the Hammersmith's Inn. The quest is bestowed by Neville Storm-hammer. He's at the back of the inn having drinks with a human (Keane d'Deneith), a Halfling (Scholes of Vedykar), and an Elf (Giggs Elorreathi). They are the quest givers for all 4 Depths quests, might as well talk to everyone if you intend to do all the quests.
All of the depths quests will require you clean up the tunnels of creatures that lurk inside. For Depths of Despair, you specifically need to kill the Troglodyte Chieftain Sslysk.