Fred Bronson and Susan Sackett made a proposal about a Wesley-at-the-Academy animated series that Rick Berman quashed, worried about the franchise stretching too thinly (ie. in case it "diluted the franchise").
A post-Nemesis animated series, "Final Frontier" (2006) was quashed when the first Kelvinverse movie was being developed instead:
https://memory-alpha.fandom.com/wiki/Star_Trek:_Final_Frontier
It still has a website!:
http://www.startrekff.com
And a Ferengi animated series with Rom and Quark, a Captain Sulu/kzinti series ("The Lions of the Night") and a redevelopment of the lost "Secret of Vulcan Fury" game were also mooted.
A post-Nemesis animated series, "Final Frontier" (2006) was quashed when the first Kelvinverse movie was being developed instead:
https://memory-alpha.fandom.com/wiki/Star_Trek:_Final_Frontier
It still has a website!:
http://www.startrekff.com
And a Ferengi animated series with Rom and Quark, a Captain Sulu/kzinti series ("The Lions of the Night") and a redevelopment of the lost "Secret of Vulcan Fury" game were also mooted.