Worth a mention is that the rumors state WB may be eyeing more serious takes on DC TV characters akin to Game of Thrones with shows on HBO. It's also said some of the new rumored TV series might tie into the DC movie universe as well.
Other rumors mention Zack Snyder off Justice League 2; Man of Steel 2 definitely happening and without Snyder; George Miller eyed for a Jack Kirby property (New Gods was previously rumored); Suicide Squad 2 in the works; the Green Lantern Corps movie would be based on Geoff Johns' Sinestro War (would be awesome!), and lots more.
Obviously take these with a grain of salt as a reddit user put together the following list from 4Chan:
Booster Gold is still in the works, treated more as a Deadpool February release film. No production date set.
Lobo is currently up in the air, being eyed as a potential TV series set in the DCEU movie universe.
Deathstroke no longer in the works. Ayer wanted to use him in Suicide Squad 2, will have an antagonist role.
Metal Men being eyed as a start for animated DC movies. If Lego Batman is successful, Warner plans to push forward development and Warner Animation Group will create the movie.
WB wants to make a few “in-universe” tv shows for the DCEU, multiple smaller teams and smaller characters being eyed. WB wants these shows to be “premium cable” type shows akin to Game Of Thrones
Fables Movie adapt canceled. Currently being eyed as a television show, although worried it may draw the comparison from Once Upon a Time. Up in the air if it will happen or not.
Sandman movie currently being developed. Giving it as much time as it needs to develop. Could very well be canceled. Joaquin Pheonix approached after Joseph Levitt left.
Sam Raimi being courted to direct a DCEU movie.
100 bullets still in development, although will not at all be marketed as a comic-related movie. Will have the Vertigo banner, but will be along the lines of Kingsman. Was envisioned as a “Sin City” type film, but is currently now a singular story. Will focus on one man’s story with the gun, and have appearances throughout by the Minutemen and the Trust.
The Question being developed for HBO as a smaller scale “gritty noir” show.
Suicide Squad 2 production begins soon, Ayer started writing the script in July, expected to shoot late-spring 2017. Will reportedly be dialed back from SS1, with less CGI, a more human threat, and no pop music at all. Slightly lower budget.
George Miller attracted to making a Jack Kirby property movie, working on Mad Max sequel in-between potential DCEU movie.
Man of Steel 2 is happening, Snyder not returning to direct.
Snyder no longer wants to return to direct JL 2, has opted out. Plans to direct a smaller scale movie for next project.
Shazam to be a one-off movie unless it does extremely well.
Cyborg currently up in the air. If he's a breakout character in JL, he will get a movie, if not, it'll be repurposed.
Legion of Superheroes canceled. Deemed “too early” to be developed.
Darkseid could potentially be saved for JL 3, having more background development in other movies for New Gods and Apokolips. New Gods property being heavily eyed as a film.
Green Lantern Corps will be an adaptation of Sinestro Corps War. Will have Guy Gardener, John Stewart, and Hal Jordan as the only human lanterns. Red Lanterns won’t appear but will be teased.
JSA was originally being worked on, expected to be teased in Wonder Woman with them being in WWI instead of WWII heroes. The idea was scrapped due to it not fitting the general plot of Wonder Woman. It was decided to relegate these characters to the CW shows.
Scalped being worked on by WGN network. Was held up with Doug Jung working on Star Trek movie. Jung expected to show run the series. Geoff Johns wrote the pilot.
WB wants to keep a 3-year release schedule with solo movies for A-listers . Wants to keep diversity in the lineup and keep filmgoers interested without being fatigued. On DC Animated movies, plans are to increase production to 4 movies per year. Doing “event” animated movies with a limited theater release ala Killing Joke will probably happen yearly.
Old scripts being revitalized as animated movies might still happen. Batman Beyond script by Boaz Yakin has been floating around.