The Dungeon Master's Guild says:
Under the DMs Guild program, you can publish D&D material that either
has no setting or
uses the Forgotten Realms or Ravenloft setting.
So, let's assume that I'm running a game in the "Shadowfell" which entails a homebrew continent that doesn't exist in the Forgotten Realms canon?
Furthermore, what if it has a pantheon of gods that doesn't exist in the Forgotten Realms canon?
Clearly, it's not canonically "the Shadowfell," but other than that it functions the way that the Shadowfell does. Are either of these modifications generic enough that I could publish them under the Dungeon Master's Guild?