defunct
Meaning: no longer used or existing
Usage: They planned to turn the defunct schoolhouse into a community center.
obsolete
Meaning: no longer used, out of date
Usage: With the inventions of tape decks and CDs, which both have better sound and are easier to use, eight-track players are now entirely obsolete.
extant
Meaning: existing, not destroyed or lost
Usage: My mother’s extant love letters to my father are in the attic trunk.
derelict
Meaning: abandoned, run-down
Usage: Even though it was dangerous, the children enjoyed going to the deserted lot and playing in the derelict house.