[Ghostbusters] Timeline before the reboot

• 1984: the first movie (events of the first movie; the Ghostbusters are fired from their university job, start the business together, gain notoriety and defeat Gozer)
  • 1984-1989: The Real Ghostbusters (the Ghostbusters continue to operate as the city's premiere exterminators of the paranormal, but gradually work begins to dry up and the lawsuits over property damage continue to mount)
  • 1989: Extreme Ghostbusters (Egon, the last Ghostbuster still openly combating the paranormal, takes on four interns. Although this arrangement doesn't last very long. When Ray Stanz returns to New York to open a bookstore, Kylie, the most competent of the interns, becomes his employee)
• 1989: Ghostbusters II (after the long hiatus, the Ghostbusters finally cross paths again and, responding to the threat of Vigo the Carpathian, they reunite, this time for good)
• 1991: Ghostbusters The Video Game (the Ghostbusters are granted a contract with the city to manage all future paranormal threats, complete with a liability shield for any future damage done to the city. The Ghostbusters acquire a new member, though he soon leaves to manage the new franchise in Chicago. They also defeat the ghost of Ivo Shandor, who in life was a deranged Gozer cultist)
• Late in 1991: Ghostbusters (IDW) (more ghostbusting occurs. Among other things, the team travels to various haunted spots across America, find new competition in the Ghost Smashers, have a brush with an FBI agent who is obsessed with aliens, and even meet the Transformers)

I guess Afterlife could be canon down the line. Maybe.