The Book of Jashar
A lost book quoted twice in Scripture — not a person.
The Book of Jashar is a book, not a man. Scripture quotes it twice and never again: Joshua 10:13 cites it for the day the sun stood still over Gibeon, and 2 Samuel 1:18 cites it for David's lament over Saul and Jonathan. Both times the writer points to it as a source his readers already knew, so it was evidently a collection of Israelite poetry or war songs. No copy survives, and the Bible tells us nothing else about who compiled it. People sometimes meet the name "Jashar" in a genealogy list and take it for a person; it is not.
Everyone in this list
David
King of Israel who defeated Goliath and established the Davidic dynasty
Jonathan, Son of King Saul
Prince of Israel and loyal friend of David who died at Mount Gilboa
Joshua, Son of Nun
Successor of Moses who led the Israelites in the conquest of Canaan
Saul
King of Israel who was the first to rule the United Monarchy before being rejected by God