It turns out that the spinoff movie Rogue One: A Star Wars Story originated as the pitch for a live-action Star Wars TV series.
A rough sketch of the new idea that ultimately became Rogue One: A Star Wars Story was originally drawn up as part of plans for a since-abandoned television series, instead.
Rogue One is the first one of these projects (operating under the “A Star Wars Story” banner), exploring the story behind the Rebel Alliance’s pre-Episode IV: A New Hope theft of the original Death Star plans.
I thought that idea of the mission to steal the Death Star plans, telling that story could make a pretty good standalone feature as well.