Greenery Goblins

Nobody wants to play a Halfling. They're short and plump and they like farming and relaxing and generally being country bumpkins. I get the impression Raggi knew nobody would ever want to play a halfling too, considering how boring the Halfling is as it levels up. Every second level is a dud where the only thing you get is a bit more health.

So I changed them to Goblins!

I like my goblins to be wacky and insane and stupid, they talk in a silly voice and do contrary things.
But considering it's a player behind a Goblin character, and PCs tend to be somewhat cunning and intelligent, it creates an interesting mismatch when the their goblin doesn't act like any of the regular goblins out in the world.

So, goblins -

Goblins are technically a type of motile vegetable. That's why they're green

Goblins live in hives below the ground, and much like leafcutter ants they live on the fungi and lichens that grows on the rotting matter they bring into their mushroom farms.

Goblin hives themselves are a disorganised affair, leading to many dead-ends and switchbacks as the goblins get bored with digging or forget where they left off or get eaten by the creatures that tend to lurk in the forgotten nooks and crannies.
The very oldest hives are immense, cutting through natural caves and adjoining other subterranean delvings.
The dwarves hate them because they have no regard for structural integrity and dig into dwarven tunnels and steal their gold and and let all sorts of dangerous creatures into the mines.

Despite being plants, they have similar physiological needs to humans.
They must eat, for their stomachs are sacks lined with roots and filaments and symbiotic fungoids, drawing sustenance from the food in their bellies. Once the mulch is drained of sustenance, they excrete it from their pores. They are always covered in muck.
They must breathe air, for they have developed to suit life beneath the reach of the sun. They drain their food of nutrition in order to power their bizarre subterranean photosynthesis.
A goblin sealed in a small room will never run out of air for it exudes oxygen from its skin.

They mostly reproduce asexually by budding. These buds tend to grow on their long noses, and are commonly mistaken for warts. Pick off a bud and plant it in rich soil, and over time it will grow into a fully formed goblin. Pick it too early and find a creepy mandrake thing. It's cry does not kill, but it'll scare the shit out of you when you pull it out of the ground.

Goblins formed via budding are asexual, and the reason why the common perception of the goblin is one of madness and unpredictability. They are the worker ants of the goblin tribe and they are rude, stupid, greedy, and fiercely loyal.
Worker goblins can themselves bud off even more goblins and so they quickly repopulate after tribe-destroying disasters. As a result, worker goblins have a singularly suicidal mindset and will happily give their worthless lives for their tribe.
This complete disregard for personal safety, paired with easy access to potent fungal reagants, predisposes these goblins towards alchemy and machinery. Unfortunately, their oxygen-exuding skin makes them especially flammable, and their attention deficit nature and capricious mindset makes them liable to "forget" to make their machines safe in any way.
Worker goblins are vindictive against their fellows. They create nonsensical traps in thoroughfares, hoard treasure in dangerous out-of-the-way places, and otherwise mess with each other in manners both deadly and stupid.

There is another caste of goblins which commands and controls the workers. These are known to the worker goblins as Budmothers and Budfathers, to sages as Matriarchs and Patriarchs, and to the layman as Hobgoblins.
While they are physiologically similar to the asexual worker caste, they aren't insane. Unique where the bud-goblins are identical, capable of rational thought and future planning where the bud-goblins are irrational and capricious, they are the natural leaders of their tribes.

The goblin reproduction process itself involves doing something fairly complicated with anthers and stigmas and results in the male and female fusing into one big entwined seed . This seed is planted in a fungus patch, well tended by the worker goblins, and allowed to grow into a large flowering plant which puts forth a single large bean over the course of several months.
When this bean opens, revealed within are 4 to 8 baby Hobgoblins, which are raised to maturity by the goblin tribe at large. They refer to each other as Podbrothers and Podsisters.
Some stay with their tribe, helping to control and lead it to greater industry with their tactical thinking. Others strike out into the world above, seeking a mate with fresh genetics and a place to start a new hive of their very own.

These latter goblins are prone to joining adventuring parties, delving into depths and exploring far across the land in search of a nice place to set up a new hive.

How do they work? Check it out here!