quality:correction, linguistic:paraphrasing
Classifications

Various folklorists have proposed classification systems for fairies. Using terms popularized by W. B. Yeats, trooping fairies are those who appear in groups and might form settlements, as opposed to solitary fairies, who do not live or associate with others of their kind. In this context, the term fairy is usually held in a wider sense, including various similar beings, such as dwarves and elves of Germanic folklore.

In Scottish folklore, fairies are divided into the Seelie Court (more beneficently inclined, but still dangerous), and the Unseelie Court (more malicious). While fairies of the Seelie Court enjoyed playing generally harmless pranks on humans, those of the Unseelie Court often brought harm to humans for entertainment. Both could be dangerous to humans if offended.

Some scholars have cautioned against the overuse of dividing fairies into types. British folklore historian Simon Young noted that classification varies widely from researcher to researcher, and pointed out that it does not necessarily reflect old beliefs, since "those people living hundreds of years ago did not structure their experience as we do."