Zak S. posted a neato keen way to pitch 5e campaign settings. My contribution:
Forgotten Realms: A Days Of Future Past-style dark future in which Lolth has devoured all but a handful of her fellow deities, leaving only the most interesting. As a result of her dominance, she has spun a sun-occluding cocoon around the entirety of Faerun, while the remaining (otherwise hostile) deities’ followers strive desperately to survive or escape the spiderscape that their world has become.
It’s not my best idea and I am certainly no great expert on the Forgotten Realms, but it seemed like fun to try and flesh the concept out.