Brownies of Scotland were friendly little people who lived with families, working around the house when the family was sleeping. Elves of Germany were mischievous, spiteful creatures who had no souls. Goblins and Gnomes are basically French. They are bad tempered, household spirits who like to live in dark places. However, when in the mood, they are helpful.
Gnomes are fond of tunnels, so they work in mines.
Gremlins are probably English and are associated mostly with airplanes. They are blamed for everything from all the crews' problems to any mishaps that befall the plane. The Leprechauns, of Irish nationality, are rich and stingy. They will not part with their crocks of gold, and vanish quickly at the smallest hint of danger. Trolls of Scandinavia can either be dwarfs or giants.