There are multiple quests that require you to kill the same things

Level 31-40 Priest Quests: While not specific to Priests alone the following Mabinogi Gold is very useful in this level range.

Anpu of Grim-horn Tribe on server Draenor sent in the following, Draenor for any horde character level 31-40 the best place to Quest is definitely Strangle-thorn Vale (AKA STV) you can fly thought the Q's there. Of course start with the hunting quests from the camp by the river and be sure to have the page quest too.

As you go along the pages will drop for you, at the end any leftover ones you can buy from the Auction House (AH). Make sure as you go to frequent South of Grom'Gol at Booty Bay.

In the tavern near the bank there are a lot of quests including some very rewarding chains. There are multiple quests that require you to kill the same things or get things from the particular Mobs another quest asks you to kill. You can use wow gold buy some weapons you help you do it.

Just keep an eye out and ask around. Also there are a lot of quests that involve the Trolls like Bloody Bone Necklaces and the Troll Tusks.