You mean Season 2? Cause I read that Season 1's already on DVD.
As to your original point... I couldn't find any classic fairy tales that involve or have a goblin character. So I went to the Disney Wiki to search if there any viable goblin characters that could open the possibility of leading into the Labyrinth. Disney would have to get permission from JHC or whoever holds the rights to the franchise, but consider:
1 Sydney Glass, the entity trapped inside Regina's Magic Mirror was a genie who brought venomous vipers from Aggrava.
There are the members of the traveling circus who were Aladdin's first enemies, Minos, Fatima, and Aziz. They were transformed into a minotaur, harpy, and goblin respectively by the Destiny Stone. As a goblin, Aziz had magic breath that created all manner of illusions. Illusions that prove to become obstacles for Aladdin and Razul when handcuffed together by a pair of handcuffs that tighten whenever they argue with each other.
So you have a goblin character with powers of creating illusion obstacles, changing an entire environment based on his whims. The only problem here is the eastern/oriental origins or theming for such a character.
2 Creeper, an original character from the movie version of The Black Cauldron, depicted as a goblin.
The movie and book series takes place in the kingdom of Pridain, but it definitely has a European feel to the overall story. At the end, Creeper dons a set of horns mocking his former boss, the Horned King, mounts a gwythaint and flies away to supposed freedom. We never know where he escapes to though. It'd be plausible, like Red/Ruby he fled to an unknown goblin community such as an enclave like the Goblin City.
Knowing what they've done with Rumplestiltskin/Beast, Aziz and Creeper could be merged into a newly-named goblin character who has powers to create illusory traps, change the world around him, and ruler of a goblin civilization.
You get that established and then who knows, the door could be opened to finally having Moraine depicted in live film.