I will take some bits from the Forgotten Realms wiki about the Quaggoth to use as reference here. First, what is a Quaggoth:
History
Originally believed to have been bred by drow magicians as a slave race, the quaggoth escaped and filled their own niche in the Underdark.
Personality
Quaggoths feared no creature. Though they were dangerous hunters, they were just as often prey for other predators of the Underdark. Quaggoths could be trained as servants and guards if captured young.
Description
Quaggoths were humanoids with long, shaggy, white hair covering their entire bodies. They wore no clothing, with the leaders of packs being the exception.
Warlike and vicious, they roamed the Underdark looking for prey. Drow sometimes enslaved them as guards and spider handlers.
Ecology
Quaggoths were nomadic hunters. They changed territories periodically. In each new territory, they claimed a central cave as a lair, leaving treasure with a few guards. The rest of the tribe hunted, returning periodically to rest and change guards.
I have to mention that since Quaggoths are intelectual property from Forgotten Realms (owned by Wizards of the Coast), they cannot be converted to Pathfinder by Paizo.
Stats-wise, they are large carnivorous humanoids that can enter a berserker rage and are immune to poison. Their stats can be found on the Monsters of Faerun.
Troglodytes
The troglodytes are a bestial sentient race that is often enslaved by more powerful races in the underdark, specially drows. From Golarion Wiki:
Troglodytes are a barbaric and vicious underground-dwelling humanoid race. They are most common in Nar-Voth and are favored slaves for many of the other races of the Darklands.
In golarion, they are similar to quaggoths in the sense that they are bestial looking, live in tribes, have shaman as their religious leaders. Even being one of the oldest races that live underground, they are often enslaved by others.
now it is the troglodyte that hides in caves and lives the life of a feral savage.
Stats-wise they are medium, and instead of berserker rage they have their stench ability. That said, their combat power is much weaker than the quaggoth.
Now, the drows of golarion are also different from the ones in forgotten realms, specially due to their fleshwarping practices. They have created many new creatures using fleshwarping, and they have bred a new type of troglodytes called the Ghonhatines.
Ghonhatine
The ghonhatines are fleshwarped troglodytes, which turns them into dinosaur-like humanoids that carve for flesh. They look more like sentient crocodiles than troglodytes. They are a slave race to drows and rarely seen outside of that lifestyle.
Stats-wise, they are much stronger, being a CR 10 creature.
Morlocks
The morlocks could also fit thematically, as they are a tribal and nomadic race, which is based on the ability to hunt. Their stats makes them stronger then troglodytes, but they are also medium and have few abilities other than being really good at jumping.
Gugs
The gug of golarion are the largest sentient humanoid race to inhabit the Darklands. They are bestial, live in tribes and are feared by the other races.
From Into the Darklands (page 36):
The largest of Sekamina’s races are the gugs, enormous giants covered with coarse gray or black fur, with arms that split at the elbow into two forelimbs each tipped with a taloned paw, and a hideous face overwhelmed by an immense, vertically-opening, fanged maw.
Their stats also make them much stronger than your average darkland encounter (they are CR 10).
None of those creatures have the same appearance as the Quaggoth, nor the same stats, but they are what replaces them in theme and feel, while some of them replace their role in the darklands.
