I am currently running three games in the Wilderlands of High Fantasy (Necromancer Games). Much like Tim of Gothridge Manor the most visible change I have made to humanoids regards goblins.
When we started the campaign, I announced it as a “shadow” campaign. The players would start as the agents of the Alder King, a forest spirit that protected the goblin city of Grezneck. I stole this city from the third book of Rappan Athuk (Necromancer Games). On a whim I decided that goblins were possible starting options for player character.
I quickly invented some stuff to go along with it. Inspired by the birthing of orcs in The Lord of the Rings movie, my vision of earth blood being responsible for magic, infusing the underworld with eldritch energies, being the reason for the myhic underworld, spontaneous creation taken to the next level – inspired by all this I decided that goblins were sexless humanoids that spawned from underground mud, short-lived, venerating Orcus who promised to prolong life by unnatural means…
By playing goblin characters, my players have started shaping what goblins are. They are vengeful, cowardly, murderous, they lack empathy, scheming, they will bribe dragons, they will dabble in sorceries, if they don’t worship Orcus then they worship Nergal instead, and if not Nergal, then Set. Underworld and death, underworld and pestilence, or poison and death… Those are the goblins in our campaign.
The first Wilderland campaign uses D&D 3.5 and the two other campaigns use Labyrinth Lord. I’ll be using the goblin character class by John Wilson should any players in the other two campaigns want to play goblins.