Bare Necessities

Very easy to do!

I used Pelagos to complete this achievment.

Easiest bosses to do this with, are Nuuminuuru and Craven Corinth. Both fights are very easy, and don't need any equipment to do it.

For Nuuminuuru, just stand behind a pillar, kill all the adds that don't LOS you, kill the exploding fairy either with 1 or with Unleash, and just slowly kill the boss. Keep in mind that he loses insane amounts of HP if you Unleash alot of mobs.

For Craven Corinth, as long as you learn how to use the shield ability just in time (when he teleports, you don't need to dodge the sequence since you just immune it), and how to kite him since he melees quite much, no equipment is required for him.

I achieved this easily by fighting [npc=173710] with Kleia.

Don't focus fire on Nuumi himself, but rather focus on the faeries. The order of importance goes:
Volatile Faery > Symbiotic Faery > All other faeries

Get on the volatile faery as soon as it appears, and two hits of ascendant strike will do it in. Same for the symbiotic.

Good luck!

If you do Craven Corinth on Wisdom difficulty you can complete Curse of Thirst, Bare Necessities, and Charmed, I'm Sure all in one go. Please note that it is difficult without equipment but it is 100% doable.