Sac items are required for a lot of Weapon and Armor synthesis and upgrades, here’s a complete list of which monster drops what sac.
How do they drop?
You only have a chance of them dropping upon capture or defeat of a monster. You cannot get them from breaks or carves.
Poison (LR) / Toxin Sac (HR)
Pukei-Pukei will be your target for the icky poison and toxin sacs.
Electro (LR) / Thunder Sac (HR)
All you need do is seek out Tobi-Kadachi in both Low and High rank for these sacs.
Flame (LR) / Inferno Sac (HR)
A variety of monsters drop these sacs, here we go! Anjanath, Rathalos (HR Azure Rathalos too), Rathian (HR Pink Rathian also). Not forgetting Lavasioth & Uragaan, who drop Inferno Sacs only, as they’re HR Monsters.
Aqua (LR) / Torrent Sac (HR)
The wet boy, Jyuratodus is the monster who will drop all of your water-based sacs.
Frost Sac (LR) / Freezer Sac (HR)
Legiana, the majestic beast is the one who drops Frost and Freezer sacs. Good luck pinning ’em down, though.
Sleep Sac (LR) / Coma Sac (HR)
Big bad Radobaan will drop Sleep and Coma sacs after a big battle.. potentially if you’re lucky.
Paralysis (LR) / Omniplegia Sac (HR)
Finally, Great Girros drops the Paralysis and Omniplegia sacs.
Other useful items
There’s a few other great items that are often sought out with Monster Hunter World. Let’s have a quick look.
Screamer Sac (All Ranks)
Noios in the Wildspire Waste will also drop Screamer sacs used to make Screamer pods.
Fertile Mud (All ranks)
Last but not least, Barroth has a habit of putting Fertile Mud about the place.