Hello internet. Below is a list of the quests needed to be done for the achievement done that. A few tips for the quest I like my monsters rare is below the quest list if you know any better better spots please by all means let me know in the comments and I will change it in the tips. If you downvote me please let me know why so I can update my list or add anything.
Quests with a * are main missions
*Savage Lands
*Professor Nakayama, I Presume?
*A-Hunting We Will Go
*The Fall of Nakayama
An Acquired Taste
Egg on Your Face
I Like My Monsters Rare
Palling Around
Nakayama-rama
Still Just a Borak in a Cage
Urine, You're Out
Follow the Glow
The Rakk Dahlia Murder
Now You See It
Ol' Pukey
Big Feet
Voracidous the Invincible
All the missions are pretty simple except voracidous the invincible and I like my monsters rare.
Voracidous the invincible is a pretty hard raid boss if youre his level but if you are lvl 50+ it is an incredibly easy boss on normal mode so i advice doing this with a high level character.
A few tips for I like my monsters rare. You need to hunt a few rare beasts:
-Pink boroks 8
-Tailless scaylions 8
-Two-legged drifters 6
-Albino skags 5
-Slagged spores 4
The places I advice dont always spawn the desired creature and you may need multiple attempts of killing the beasts before actually finding one. I can advice you but cant battle the random spawning generator. I tried it once it didnt end well.
pink boroks
These beasts can be found in almost if not all area's of the DLC but a good place to hunt pink boroks are through the tunnel beneath the fast travel to hunters grotto. Fast travel to hunters grotto and hunt the packs of boroks through tunnels on your way to scylla's grove once youre near the travel point go to the main menu and start it up again and fight yourself back towards scylla's grove. rinse and repeat.
Tailless scaylions
Scaylions are also not very rare. these beasts reside in most area's of the DLC but an easy scaylion pack lives near the fast travel station of Ardorton station. You can actually do this one simultaniously with the slagged spores. To do this one well you guessed it teleport to the fast travel, kill the pack, go to the main menu, start up your game again and kill the beasts again. rinse and repeat.
Two legged drifters
Drifters are only found in Hunters grotto. An easy way to farm these is use the fast travel to the hunters grotto lodge and walk outside but dont jump down. To the west of the lodge one drifter spawns and to the north east ish two drifters spawn near the catch a boat station. kill them then main menu etc.
Albino skags
They spawn in Scylla's grove and are found in multiple packs. Secondone pointed out to me that while busy with the quest urine your out there are quite a few skags to kill here. After the quest you can come back and kill them again and again just make sure to use use a fast travel close to the location and close the game for them to respawn.
Slagged spores
These are supposed to be the most rare ones. They spawn in Hunters grotto, Candlerakk's Crag and Ardorton station. One spore that can possible be a slagged spore spawns in Ardorton station. This objective can be done simultaniously with the scaylions. Fast travel to Ardorton station and down the slope is a spore that can be a slagged spore. Kill it, go to the main menu start your game again and repeat.
Thanks for reading i hope my guide helped!