Growling Yawl fragments are mob drops. There are some named mobs that drops those fragments with %1 drop rate. Also some normal mobs has a chance to drop. But it is just %0.2. Let's start with normal mobs.
Freed Yetis in Rookborne Basin has a chance to drop.
database ss: 
Mobs in Halcyona Castle are used to have a drop chance (%0.2). But this information have been removed from database websites. If anyone drop one, please let us know!
NAMED MOBS! (%1)
Those Named mobs' respawn time is 30 mins.
People less than 55 levelcan kill 4 more named mobs:
*Shy Denly
*Wandering Captain Kingston
*Umbras's Spirit
*Kyrios Disciple Klei
55+ levels
Gweonid
Ventix the Stormwhorl
Dahuta Slave Belucci
Note: Not sure if those 2 are still dropping. Let us know if you get a drop please! I killed like 100 times after ancestral, no luck.
Halcyona
I got drops from every named mobs in Halcyona. So I can assure you they drops!
*Wolf Trainer Paul
*Metal Golem #29
*Knight Captain Herbert
*Senior Knight Albert
*Brainwashed Butler Heinmann
*Golden Goblet Leader Denslow
*Brainwashed Tutor Evelyn
*Grendilla the Witch
Grendilla is on the top floor of that small castle. I was too weak to kill her 4 years ago so I didn't take a screenshoot I will add screenshots If I don't forget.
Rookborne Basin
*Imprisoned Yeti Lerox
*Imprisoned Yeti Krox
When you got hearts of Lerox and Krox, you can summon Fasrox in near Jar. Following video for Fasrox is not mine.
*Imprisoned Yeti Fasrox
You can watch my old video. Unfortunetely doesn't include Rookborne ones and Grendilla the Witch. Also sorry for annoying songs
I wish you all good luck on farming!
