Libby: A psychologist and possible love-interest for Hurley.
Ana Lucia: Former cop and murderer. Resident hot-head.
Mr. Eko: Nigerian warlord and drug dealer. Has re-imagined himself as a priest and holy man on the island.
Henry Gale: Crashed his balloon on the island. Imprisoned by Locke and Sayid.
Rose and Bernard: Appear when needed. Not needed very much.
Desmond: Hatchling and button pusher, disappeared into jungle.
Rousseau: Stranded on island sixteen years ago. The Others kidnapped her daughter.
Aaron (AKA Turniphead): Claire's baby. Born on the island. May be the devil.
Cap'n: As-yet-unnamed, grizzled leader (presumably) of the Others.
Walt: Snatched by the Others. Good with the island internet. Occasionally appears in the jungle, dripping wet and talking backward.
Michael: Gone all Bear Grylls in the jungle looking for Walt. Ain't been seen in four episodes.
Two Blonde Kids: Tailies abducted by the Others.
Cindy: Tailie Oceanic stewardess, abducted by the Others.
Shannon: Shot dead, accidentally, by Ana Lucia.
Boone: Shannon's step-brother. Died of injuries from fall.
Marshal Mars (AKA Marshal Gunfingers): Mercy-killed by Jack.
Ethan Rom: Has an anagram for a name. The Others' spy. Killed by Charlie.