Annihilation writer/director Alex Garland said that if he were to do another comic book movie, he'd like to work on DC's Swamp Thing. Garland revealed that as part of a Reddit AMA earlier this after he was asked "If given the chance, which comic book characters would you want to write/direct?"
Garland's Annihiliation has a bit of the Green that Alec Holland could easily get used to.
Garland has a history with comic books - his father, Nicholas Garland, is a reknowned political cartoonist. Also, Garland wrote the 2012 film Dredd.
Warner Bros. has no announced plans for a Swamp Thing movie, however no replacement director for Justice League Dark has been confirmed.