If you are interested in a great, mysterious, emotional flashback fanfic series, check out my friend' s Realm series on AO3 - Crowley and Aziraphale keep being yanked out of reality in different historical periods, to find each other again and again but then they have to "wake up" Rated E. (her art too) Worth a read :)
https://archiveofourown.org/works/53019451
![The Realm Series - Chapter 1 - Andimyon - Good Omens - Neil Gaiman & Terry Pratchett [Archive of Our Own]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)