Forest Goblins are a subrace of greenskins from Warhammer Fantasy, and are the resident American Indian-expies despite living in not-Europe.
A recent addition to greenskin lore, only existing post-7th edition.
In the early time of the Warhammer World (AKA Mallus by fan-name), the primitive greenskins spread from not-Asia (where the Old Ones may or may not have accidentally introduced them as spores stuck to their dimensional spaceships, yes you read that right) into the only place that's relevant which is not-Europe.
Most greenskins came to dwell in what is known as the Badlands, AKA not-Southwest Asia/Middle East, which they continually strip of virtually all life and otherwise fight amongst each other as a disorganized rabble until they somehow gather in a big enough group to head west and destroy civilization for lulz. The standard Orcs and Goblins are technically Plains Orcs and Plains Goblins, but are generally just called Boyz.
The most primitive of the greenskins, the Savage Orcs, remain the example of what the first Orcs were like because Savage Orc "KULTURE" almost never changes and the few changes that do occur only survive in living memory. The closest example of Savage Orcs among the Goblin breed, Forest Goblins, have changed, in few but major ways.
Residing in the dark monster-filled forests of the Drakwald, the Goblins managed an existence without being bullied into doing work by their larger kin. Like Savage Orcs, the Forest Goblins stuck to their original culture based on color-based meaning and...not much else.
The only problem was the other inhabitants of the woods; spiders. Billions of them. As large as the Games Workshop writers can grimdark into existence and still fit on the planet ("There are as many miles of forest as the plot requires."). The Goblins were in a BADLY losing war with them where only the fact that Goblin deaths directly result in population replacement via spores kept them from extinction. The Goblins did not win this war; they adapted to it. Without any enemy or contact other than the spiders, the Goblin culture revolved entirely around them. They sacrificed each other, raised and tamed the medium-sized spiders (meaning the size of a horse) to use as mounts, and ate nothing but smaller spiders with eventually the Shamans figuring out what spiders they could eat (or they could shove in their mouths to get a tongue full of spider-bite venom) to go into trances and see into The Warp where they discovered an entity called the Feaster from Beyond (known commonly as the Spider-god). As of Age of Sigmar the Spider-god was an ordinary spider at some point that bit Gork (or was it Mork?) which tied its destiny to them and granted it divine power so the Spider God is a legit god rather than a kunnin' Daemon or a large mortal spider the Goblins worship due to being venom-addled gits.
As time went on, Forest Goblins began developing spider-like traits like eyes coming in even numbers higher than two, extra arms, fangs, envenoming everything, using webbing to build structures (and not get trapped in them), and even managing to coax their gigantic spider "demigods" (now it turns out that was correct mind you) in the form of the Arachnarok Spiders as their champions/mounts. Initially the Arachnaroks were giants who were undefeated during the Goblin/Spider war that would prey on them at leisure, but as more and more Shamans communed with the Spider-god they learned dances that the Arachnaroks recognized as indicating kin and treated the Goblins like their own young (of course these being spiders they do eat any that get close to their mouths). This long time to adapt and become something that isn't a handful of green mushroom monkeys being eaten by giant spiders explains their absence from earlier editions.
Oh. They also wear feathered headdresses, live in far more tribal tribes than other Goblins, have a culture that revolves around their mounts, and are fighting a losing war against invading people from Europe intent on logging their lands. Yeah... Scythians.
The Forest Goblins are as close as you can legitimately get to "did nothing wrong" with greenskins; they only waged war on the Empire when Empire loggers managed to nearly reach the Warhammer Underdark called the Black Valley and the Pit Of Many Eyes, where presumably Warhammer Ungoliant lives and wiped out many Forest Goblin tribes. Snagla Grobspit is their only important historical figure, and Forest Goblins have never had a recorded WAAAGH! or participated in a major way in one. That's not to say that Forest Goblins are Ewoks, they still enjoy torturing things to death and general murder/eating sentients (as do Ewoks, but you get the point). They just don't seek it far and wide like others of their race. Oddly enough, Forest Goblins rarely fight Wood Elves, their racial mission statement being to join other greenskins only for the purpose of wiping out Empire incursions and to wage wars of dominance with their hated (but tasty) foes the Beastmen. Although entirely willing to sacrifice humans, they usually perform blood sacrifices of their own and do so when without other races to kill.
Ever since taming Arachnaroks, most Forest Goblin villages are built near their lairs. Each Arachnarok is the identity of their tribe. The smaller spider mounts used by Forest Goblin Spider Riders come from various species, with named ones being the "Tilean Greybacks", "Drakwald Mancatchers", and "Scarlet Deathheads Of The Great Forest".
Forest Goblins had no special part to play in The End Times.
Age Of Sigmar
Most races in AoS are functionally identical to before the end of the world other than almost every character being dead and having..."interesting" renames.
Like in Warhammer 40000, Goblins are Grots. Otherwise Forest
Goblins Grots are the same.
A new variant of
Goblins Grots were introduced in Warhammer Quest: Silver Tower however. Scuttlings are if Goblins Grots could have sex and produced a child with a spider and their offspring conceived the child of also sexually-reproducing Night Goblins Moonclan Grots. Scuttlings are multi-eyed hunchback Goblins Grots wearing ling hooded black robes with six limbs, the middle limbs sometimes being like a spider's. They use bows, spears, and hand weapons and hide from the light in corners waiting for weak and unwary foes to walk into their webs. These new models have become very popular and even grumbling Fantasy players have been incorporating them into Forest Goblin armies.
Spiderfang and Moonclan Grots have been recently unified in the Gloomspite Gitz faction. The Spiderfang tribe, like the Moonclan, reveres the Bad Moon, albeit they believe it to be the giant egg of the Spider-God.