I really don't think Vettel will be considered by the top teams, as they have solid driver lineups. And I somewhat doubt he would consider a Renault level team, as his ego seems to remain at a higher level than his driving in recent years.

I see stepping away to retirement as the probable outcome.

If he does settle for a lesser team, maybe he can add to the list of car carnage he has created with his fellow team drivers. I think at some point he has taken out every team mate he has had, and usually in spectacular form. And the explanations are golden as well, as in his mind he is rarely if ever at fault.