ELSEWHIRLS! Beyond the plots you know! Stories that wouldn't, couldn't or shouldn't exist! Imaginary stories and impossible tales!
In other words, alternate-universe stories in the style of Marvel's What If? or DC's Elseworlds.
Often, stories that have been retconned out of continuity are referred to as being Elsewhirled.
See also the List of Elsewhirls.