I might as well start the wild speculation for the last episode.
1) Tony gives up all interest in Jersey for Phil's scalp- With this new El Duce persona Phil has I am sure there must be someone in the 5 families willing to give up his whereabouts for all the joint projects in Jersey. I would say Carmine JR. but it would take a miraculous 180 for him to pull this off. Maybe someone is still angry enough over the Rusty murder to do something. 20%
2) Scarface final scene Sopranos style- Highly unlikely as that would be too expected and Chase is known for the swerve. I don't think the Bobby special even lets off a shot during the finale.5%
3) Tony fades away- Somehow Tony gets out alive and exchanges some crucial information for Phil's whereabouts,, after the hit Tony quits the life. No snitching, no witness protection, on his own terms he leaves. Carmella just made over a half a million dollars on the sale of her home along with the other provisions Tony has left for her, Meadow is well adjusted and tough enough to move on without him, the sticking point is AJ. 50%
4) Tony goes to jail- This is slim. All of the informants we know about are dead, the biggest thing over his head was Christopher caving in and turning on him and he is dead as well. The terrorism angle has been diminshed by his giving information on them, so what is really left? 24%
5) Tony is abducted by aliens to launch a sci-fi spinoff. 1%