The original Timeline that started it all, melding the two movies, The Real Ghostbusters, Extreme Ghostbusters, and the Now Comics into one semicoherent continuity. Forms the basis of Ectozone fan fic continuity, but some differences have appeared over the years.
A supplemental Timeline specific to the Ectozone fan fiction continuity, or, as it refers to itself, "Timeline 8932".
Established for the Twenty-fifth Anniversary, dedicated to the "new" continuity formed by Ghostbusters: The Video Game, the comics from 88MPH, Tokyopop, and IDW, and the possible Ghostbusters 3.
I haven't updated this in a while; the ending of the "Mass Hysteria" miniseries in 2014 basically gave me a massive headache when thinking about how to deal with the massive retcon it introduced. Anyway, this is what the Ectozone multiverse considers "timeline 1423", more or less.
I won't rule out doing a timeline based on Ghostbusters: Afterlife (or "timeline 681"), though as it would only contain three movies, and possibly the 2009 video game (at the present time, it's not clear if it counts it.) it would be best handled as a separate timeline.
Ghostbusters is ©1984 Columbia Pictures. Ghostbusters 2 is ©1989 Columbia Pictures The Real Ghostbusters is ©1986 Columbia Pictures Television and DiC Productions. Extreme Ghostbusters is ©1997 Columbia Pictures Television and Adelaide Productions. The 88MPH comic book is © 2004 Sony and 88MPH Studios. Ghostbusters: The Return is © 2004 Sony and iBooks. Ghostbusters by IDW ©2008-Present Sony and IDW. Ghostbusters: Ghost Busted ©2008 Sony and TokyoPop. Ghostbusters: The Video Game ©2009-2011 Sony and Atari. Ghostbusters: Answer The Call © 2016 Sony. Ghostbusters: Afterlife © 2020 Sony. No use of characters and images associated with the above is intended for profit, or to challenge the copyrights of the above holders. Characters and ideas not appearing in the above copyrighted works are to be considered © Fritz V. Baugh and/or their respective creators