I banned orcs from my homebrew world around 1989 because I disliked how similar they were to goblins and I vastly preferred goblins.
My backstory on goblins is that "Flame Eyed" Maglubiyet was the eldest deity, the first-born fruit of the tree of life whose peoples would be later called the gods. When he arrived on the scene, only the fey existed of the sentient races, and in the shadow ancient years he and his family communed with the fey. Later, "Holy" Corwen, father of the elvish race appeared, and his people danced with the elves in ancient days. Eventually there was a war amongst the gods, which all agree began as a domestic dispute among the third born family, Uman and his vast clan. Yet there are some who say that even before this time, Maglubiyet was dissatisfied, for he thought by being first born he ought to be acknowledged ruler over all the gods, and those of younger race did not acknowledge his overlordship or render to him highest honors over all the family of the Tree of Life. At the conclusion of the war, the gods met to solemnize a great treaty. As part of the terms of that treaty, the gods abandoned dwellings on jewel-like Korrel the center of creation, now called the Crimson World for it was stained with the water of life, but by the terms agreed on in the treaty they were to make a servitor race which would be tasked with restoring Korrel to its ancient glory and healing the wounds of the war. Yet, on this matter the whole council soon rose in dispute, for they could not agree once it came to implement the treaty what manner this servitor race would take. For each thought to make the race like unto themselves, and all feared that the race should serve the interests of one god or family of gods alone. So they compromised in this way, each family would present a servitor race as its design and all seven designs would be approved provided that the race was so constructed that it would have the freedom to serve any god of its choosing or none at all. This was assented to and so the Six Free Peoples were made: goblins, elves, humans, dwarves, orine, and idreth according to the design of the six fruits of the tree of life which had ripened and bore fruit, each after the image of its creator but gifted with the ability to choose who they could serve.
To these six is usually added the Seventh, the fey and particularly the Sidhe, on whom it was said the design of the free peoples had largely depended, for they were made in the likeness of fey, yet mortal so that they might not grow to much in power.
It was said that the family of Uman was late and desultory in presenting its design, for it grieved the death of their lord and was much divided and diminished after the war. It is also said that only the family of Holy Corwen was honest in its design and presented a design without guile, according to the intent and spirit of the treaty, for in truth none trusted the others and each was already scheming how they might turn the treaty to their advantage.
In any event, in the early years following the God's war, it was the elves who first flourished and who were most active in the world, healing it of hurts as best they might under tutelage of many gods - all who would teach. And in those days, the elves and goblins danced together under the stars, and it was said or thought that the eldest days had returned. Yet even in these days, it was said the goblins began to delve deep into the earth and make many fastnesses and fortresses therein, and their ways became estranged from the ways of their kindred.
Then after the kinstrife which ended the Empire of Leaves and the destruction of all those traitors who had followed Lloth and her ways, the goblins came forth. And it was said then that they were changed in form, and horrid now to look upon, being creatures of hide and scale, horn and bone, mane and wire, tooth and claw, transformed into weapons of war, and hideous even in their own eyes. And they were diverse in form as well, having been shaped according to an evil will into castes according to their purpose, either stealthy and cunning sneaks and craftsman or towering living engines of war. And they made war upon all other races and devoured their enemies as food and with relish and sadistic glee, having become lovers of pain and violence. And it is said by many at this time, that they ceased to be one of the free peoples in truth, but had been twisted from free peoples into servitors, so that they would work the will of Maglubiyet alone and serve him only. And on account of this, in many lands to slay a goblin is not accounted murder, for they are no longer accounted one of the free people but a servitor of evil, debased and twisted beyond any redemption. Yet this matter is in dispute, and some sages say one thing and others another, so that there are also nations where goblins are accorded the dignity and rights of a free person - provided they behave themselves and follow the law. But few are the places they are trusted, for even the best of goblins can be treacherous and have foul appetites.
Goblins are complex in my game operating as both villains and PCs and having a backstory that makes ambiguous their nature in a way that is unique among almost all things. I generally will not approve a good aligned goblin or hobgoblin PC (and not one at all if starting in regions where goblins are killed on sight) because the exact nature of goblins is considered a campaign level secret only to be discovered in play and not lore I just give out to anyone.
One thing goblins certainly are not in my campaign is "an oppressed people" nor are they intended to be metaphors for any group of humans or human ethnicities. If you see that in them, well that's on you and says more about you than it does about me. The goblins of my campaign world are gleeful conquerors, slavers, and cannibals that rule over vast swaths of the campaign map and are forever threatening to pour down in terrible hordes to devour their neighbors. Goblins encountered outside of goblin lands may not meet this description, and many a goblin is just "going about their business" and it's up to the PCs to decide what they want to do about that, but the inhabitants of Korrel have very good reasons for fearing and hating goblins.
