For those of you trying to complete this more efficiently:
- Endmire has a side-quest, bonus objective, and rare spawn that overlap. The rare provides completion % to the bonus objective and counts towards Aiding the Venthyr, and the mobs you kill for the bonus objective are guarding the items needed for the side-quest. That's12% total completion.
- The pond between Pridefall Hamlet and Caretaker's Manor has a side quest chain that provides 8% completion and is pretty quick. Unfortunately the "rare" there is a treasure and doesn't overlap with Aid completion.
- Tollkeeper Varaboss at the Decimated Crossroads drops an item that starts a quest when killed, providing 4% completion total. Not worth going out of your way to get it, but if he's up while you're passing by it's worthwhile. There's another quest in the area for 2% completion, but it doesn't overlap with him.
- A Curious Invitation (starts in Darkhaven) leads to a fairly compact but long quest chain which overlaps with a group quest, providing 23% completion in about 20 minutes of effort! Most of the quests are "go here, talk and afk for a minute."
- Beast Control down at the Hunting Grounds/Banewood does not overlap with the bonus objective, but is worth doing because of how quick it is (kill 6 very common bats right around where you get the quest). Huntmaster Constantin at Wanecrypt Hill offers a quess which *does* overlap with the Hunting Grounds bonus objective. Total this is around 13% completion.
- Dredhollow has no overlapping quests, although there is a rare that can spawn. If you *do* decide to do this objective make sure you pick up the Soulbreaker Traps scattered around. Each gives 3% completion and deals AOE damage (approx half a mobs health).
- Unless you have a few overlapping WQ, Dessication bonus objective in the Ember Ward is really rough. There's a few quests in the area but none of them share credit with the bonus objective. Mob kills give 1-2% progression and there's no ground lootables that provide progression. Mobs are also spread out. Snacks for Stonehead and Rousing Aroma may be worth doing. Further west, Laurent offers "An Unfortunate Situation" which leads to a long quest chain. There's an escort, but it's overall more than 10% credit and much faster than the bonus objective at the dessication.