Force ghost

Force ghosts were spirits of deceased force-sensitives and non Force-sensitives that appear in spirit form. They are able to interact with the living, appearing in visions, dreams, or reality. Force ghosts come from the Netherworld or Chaos. The Sith were able to learn about the spirits of the dead, and when they died, they interact the same way when they go to Chaos.

History
According to the Jedi tradition, death was a natural part of life, and it meant becoming one with the Force when a Jedi died, after their bodies vanish. In death, sentient beings that were force-sensitive or not force-sensitive, were able to enter the Netherworld, and communicate with the living. Deceased Jedi would also come down to force-sensitivees and reveal the mastery of certain obscure paths of learning which could avert it.

Jedi

 * Xiaan Amersu
 * Adam Antura
 * Sadie Antura
 * Crado
 * A'Sharad Hett
 * K'Sheek Hett
 * Sharad Hett
 * Corran Horn
 * Jysella Horn
 * Kara Horn
 * Kreia
 * Michael Onasi
 * Quarmall
 * Revan
 * T'ra Saa
 * Kennan Shan
 * Bastila Shan
 * Satele Shan
 * Anakin Skywalker
 * Bantha Skywalker
 * Ben Skywalker
 * Cade Skywalker
 * Jet Skywalker
 * Kol Skywalker
 * Luke Skywalker
 * Mal Skywalker
 * Mara Jade Skywalker
 * Nat Skywalker
 * Vestara Khai Skywalker
 * Jacen Organa Solo
 * Jaina Organa Solo
 * Leia Organa Solo
 * Ahsoka Tano
 * Mace Windu
 * Yoda

Sith

 * Githany (spirit redeemed before 5 ABY)
 * LaTor (spirit (redeemed before 5 ABY)
 * Ajunta Pall (spirit redeemed to the light side in 3,956 BBY)