Brownies

Holly Black and Tony DiTerlizzi's Brownie Thimbletack from their series The Spiderwick Chronicles 

Brownies are one of the most recognized fairies. They come in all shapes and sizes as helpers to families in rural communities.

In Northern England and Scotland, various spellings include Brooney, Browney, Brouney, House Brownie, Little Man, or Browny (also sometimes called Hobs). In Southern England one goes by the name Robin Goodfellow (as accounted by Carol Rose's book, which I mention down below). In Demark the Nis is said to have similar characteristics, as do the Russian Domovoi, the North African Yumboe, and the Chinese Choa Phum Phi.    

Described at an average of twenty inches high, it is unusual to actually 'see' him. On the off chance that they are seen, they can be tiny shriveled old men, furry, naked, turn into roosters at dawn, wear raged brown clothes (sometimes made of course wool) or suits of green or blue, have coal black eyes, wear caps made of felt, or have a tail such as the Lowland Brownie Wag at the Wa' (a grumpy old teetotaler with crooked legs and a long tale, who complains of a constant toothache and considers the pothook over the fire as his favorite spot to hang). Sometimes they have no nose (a common description of Lowland Brownies) only the nostril openings. In Scotland, their hands can be webbed, or have fused fingers apart from the thumb, or have no fingers or toes at all. 

Names attributed to specific Brownies are Aiken Drum, Mieg Moulach / Maggy Moloch, Wag at the Wa', Robin Goodfellow, and Puddlefoot.

In Cornwall, he is the bee keeper, as bees were considered bringers of good luck in old times. 

In Scotland, it was said every home had a Brownie; he would help with the brewing of beers and malts. His reward for a good brew would be a few drops of the best of batch poured into a holed stone known as the Brownie Stone (sounds like the name for a novel *wink, wink*). 

In Wales, his cousin is of the Bwciod (you read that right) or the Bwca or Bwbach (confusing, isn't it?). These little bogeys lean toward the Boggart in nature. They have long noses and dress in Welsh farmers clothes, are just as small as the Brownie, and will help around the farm if in good humor. They despise teetotalers. If his master happens to put him off, his goodness can't be regained and will spiral into a rampage - IE: banging on walls, throwing things, ripping clothes, pinching people, throwing people, telling everyone's inner most secrets out loud, screeching, and beating his former masters. (Look at my Boggarts page for another list of all the nasty things they can do) Retaining some sort of exorcist to sack his grumpy butt will usually do the trick.  

In certain areas, it is believed the Brownie cannot venture into daylight and will die if exposed. Other beliefs say that he simply doesn't like sunlight. Roosters can be considered their familiars, or the shape they change to when daylight comes, allowing them to work in sunlight.       

They love any work to be given when attached to a family. Farm work such as tilling the fields, grinding grain, reaping, cleaning the house and barn, churning butter, etc... They were watchful of other workers and would tell on the lazy and inefficient. They take a dish of the best cream and a new baked cake or loaf of bread (in some other instances it says that they like honey smeared on it too) for payment at the end of the day.

Similar to Dobby of the Harry Potter series, to give them sympathetic gifts such as clothes would drive them away (but instead of tearful thanks, they take offense and leave chaos in their wake. I guess they don't like being pitied?).  

Katharine Briggs' An Encyclopedia of Fairies, Hobgoblins, Brownies, Bogies, and other Supernatural Creatures recounts that the Brownie will usually become attached to a member of the family (this could be used as a Best Friend trope in a novel set in the rural highlands). Also in this version, to give a Brownie a treat specifically would drive it away. Instead, the farmer's wife would leave scraps of food in places it could reach as an offering but never as an explicitly said gift. In her book, it notes that often outside of his master's house he was a feared creature for he could be just as mischievous as he was kind. There were hardly any accounts of a female among the troupe, except for in Scotland where they were sometimes seen in small groups with one girl among them. Katharine notes the tale of Meg Moulach (or Maggy Moloch), or Hairy Meg, who was a girl and a fierce Brownie who would not tolerate abuse of her Brownie family and refused to do the house work without the aid of the other maids or house servants. Brownie Clod was said to be her mate (cross eyed cad with one too many bats in his Belfry).

Often they would hang about streams or ponds. If offended by way of negligence or sympathetic gifting, they would turn into Boggarts and haunt the household until appeased. 

Despite being benign creatures, they are adverse to Christian symbols. In one tale, it speaks of the local minister trying to surprise a Brownie with a baptism, to which the Brownie screamed and never returned. 

In some instances they like collecting things, sitting by the fire, sleeping in the shed, cellar, or attic, and are afraid of cats.

The Dobie is very similar to the Brownie, and wishes very much to be helpful. Note I said wishes, because, most everything he tries to clean or fix usually ends up worse than before he touched it. He is said to have a sweet nature, but not very bright.

These sprightly fellows can fill many different roles for the Paranormal Novel. Be it the Helper, Side Kick, Confidant for its favorite human, or Antagonist (as the Boggart version, or perhaps a wild Brownie not yet fixed to a family).

One of the most recent contemporary examples of this fairy is Thimbletack from the Spiderwick Chronicles. (in fact, you can read more about their definition of the creature here: Spiderwick Wikia)

You can find him in Book One, The Field Guide of Holly Black and Tony DiTerlizzi's series The Spiderwick Chronicles. 

I drew from Katharine Briggs' An Encyclopedia of Fairies, Hobgoblins, Brownies, Bogies, and other Supernatural Creatures, Carol Rose's Spirits, Fairies, Leprechauns, and Goblins, Nancy Arrowsmith and George Moorse's A Field Guide to the Little People, and Edain Mccoy's A Witch's Guide to Faery Folk.