Perganon was a civilisation which fell during the Last Great Time War. (PROSE: Doctor Who: The Encyclopedia [+]Gary Russell, BBC Books (2007).)
In an attempt to tempt the Doctor into joining the Krillitanes in their plans in 2007, Brother Lassar suggested they could save Perganon, as well as Ascinta and the Time Lords, by using the Skasis Paradigm. (TV: School Reunion [+]Toby Whithouse, Doctor Who series 2 (BBC One, 2006).) Later, the Doctor, as Time Lord Victorious, suggested that Perganon, Ascinta, and Gallifrey could be among the worlds that would be saved as he contemplated stopping the Kotturuh from introducing death to the universe. (PROSE: The Knight, The Fool and The Dead [+]Steve Cole, Time Lord Victorious (BBC Books, 2020).)