Season 12 left half the fandom lying on the floor looking for tissues and the other half being suspicious that there were too many deaths for them all to stick simultaneously. By now the fans are used with the "Walking Dead" twist, and coming back from the beyond does not surprise anyone anymore.
Possible Outcomes
The premiere of "Supernatural's" Season 13 starts on October 12 and the hearts of millions of fans will finally beat again (whereas the filming will begin around the middle of June). We were left with many questions from the season 12 finale.
For example, will we see Misha Collins again reprise his role or will Lucifer find a way out of that alternate dimension?
We cannot help but wonder what fate awaits Mary Winchester. She performed the ultimate act of sacrifice in order to save the world and her boys (although these two concepts seem to overlap almost always). The fans are not newbies in the famous act of bringing characters back from the dead, so if Castiel does not reappear anytime soon, that would be the most upsetting surprise of all.
The parallel universe storyline
In the parallel universe, we got to see a world where Sam and Dean were never born. If anyone was wondering it was hell on Earth. This just goes to show how important these brothers are in fabricating the storyline of the entire world.
We also got a glimpse of Bobby Singer (not the real one, but we will take what we can get, as the supernatural writers are not very generous). We cannot help but wonder if this version of Bobby will make any reappearances anytime soon, but anything is possible. The possibilities are endless (obviously since we have the child of Lucifer among us); he could show up for a couple of episodes, or even be a series regular like the old Bobby.
Actors of next season
The absence of Lucifer and Castiel have not been confirmed for next season so we still have a right to remain hopeful. Also, in the upcoming plot, we will get to see Kim Rhodes and Brianna Buckmaster again, as they have confirmed their participation. Not to mention, that there will be two episodes directed by one of the Kings of Con, Richard Speight Jr.
Furthermore, Crowley's death seemed fulfilling in some ways due to his heroic act of selflessness and redemption, thus bringing him back from the dead would be not "moving on to a new chapter" kind of story line. Castiel, however, has been a part of the show, for so long, it is difficult to imagine the Winchesters without their loyal companion.
Scooby Doo crossover
Now for a truly "Supernatural" turn of events, it has been announced that in this new season, the Winchesters will team up with none other than the Scooby Doo gang; I suppose for the purpose of solving mysteries. And not to mention, that it will take place in the fully animated world of Scooby Doo as well. There have been previous entrances in other realms such as in "Hunteri Heroici" and the real real world (one of the greatest episodes of all time); however, no one was expecting something like this.
I guess with Supernatural anything is acceptable. As long as Sam and Dean kick butt, the fandom will sit and watch them till the end of time.