The fey of the British Isles are commonly divided into a number of types. The two basic classifications were the trooping faeries, such as the Irish Daoine Sidhe and the Welsh Tylwth Teg, and the solitary faeries, such as pixies. The second basic classification was between the Seelie and the Unseelie courts. The Seelie, or Blessed, Court was made up of fey who were neutral, or benevolently inclined towards humans, and who represented the powers of regeneration and growth. The Unseelie were the 'bad' fey, those which were malevolently inclined towards humans and represented the powers of death and entropy. In mythology and in fiction, Faerie (see also fairy) is an otherworldly realm, home to the Fae or fairies, though many believe this place to be neither mythical nor fictional, but quite real. ... This article may contain original research or unverified claims. ... In folklore, trooping fairies refers to fairies who appear in groups and might form settlements. ... Pixies are mythical creatures of English folklore, considered to be particularly concentrated in the areas around Devon and Cornwall. ...

Both courts included both the trooping faeries, also often called elves, and the solitary faeries. The Unseelie are commonly described as being evil, the Seelie as being good. However, although the Seelie were the 'good' fey, they were believed to be just as capricious and often as amoral as the Unseelie.

In common usage, 'Seelie' often refers to the trooping faeries of the Seelie court, the benevolently inclined humanoid fey, who should more properly be called Sídhe. Many Sídhe, both Seelie and Unseelie, were believed to be old deities which had lost most of their power. The sídhe, (IPA ) are a supernatural race in Irish mythology — quite distinct from humankind. ...