I wonder why this little guy was left out of the later editions. In one of my campaigns, long ago, he played a major role in the players life. Was he just not used enough? He appeared in 1st and 2nd editions. With all of the many different monsters books that came out ( 3.0 and 3.5) and 4th edition, no brownie.
In folklore, a brownie is a type of hob, similar to a hobgoblin. Brownies are said to inhabit houses and aid in tasks around the house. However, they do not like to be seen and will only work at night, traditionally in exchange for small gifts or food. Among food, they especially enjoy porridge and honey. They usually abandon the house if their gifts are called payments, or if the owners of the house misuse them. Brownies make their homes in an unused part of the house(from wiki).