Ghostbusters 3: Hellbent. In the 1990s, Ghostbusters star Dan Aykroyd wrote a script for Ghostbusters 3: Hellbent, which would have seen the team transported to an alternate version of Manhattan, which is basically hell. Everybody from Manhattan has an evil doppelganger and the team has to kill the ruler of this place- Donald Trump.

Ghostbusters 3: New Blood. In 2011, Aykroyd was talking about a very different Ghostbusters 3 script, one that at the time seemed a bit more realistic: Bill Murray is retired, Aykroyd's character in half blind and the whole team is too old so they train successors, which will probably full of funny scenes.

Ghostbusters 3: The Best and the Brightest. In 2013 Aykroyd told Larry King about a Ghostbusters 3 movie in which Larry King himself would play (remember King's cameo). Ghostbusters would ask for help from a group of Columbia University students and would take place mostly around said University, as two of the original Ghostbusters themselves started out as Columbia adjuncts. There was supposed to be a part for Murray if he agreed to come back.

Ghostbusters 3: Electric Gozer-loo. Max Landis also pitched in an idea which remained just an idea. Ghostbusters turned into an international franchise with many teams, the team stationed in the original firehouse is bankrupting and tries to summon ghosts but cult of Gozer comes in, murderes Slimer (!) and tricks Ghostbusters to resurrect Gozer. Sounds cool, huh?

Ghostbusters: Alive Again. This one would feature Venkman’s and Dana Barrett’s son Chris joining a Ghostbusters team led by Jonah Hill playing a guy named Jeremy. Comic relief would come from a character named Dean, played by Zach Galifianakis. There would also be Sacha Baron Cohen or Will Ferrell, and Aubrey Plaza.

Ghostbuster Universe. This was an idea of making a Ghostbuster Universe similar to Marvel Universe with many movies and series with different actors, one of them being Channing Tatum. Sony said "no", the end.

Ghostbusters 3: The Actual Movie. With Kristen Wiig, Melissa McCarthy, Leslie Jones and Kate McKinnon, and Chris Hemsworth. It will come out soon, are you waiting for it?