I know Highschool DxD and Heaven's Lost Property both make a bit of money, I don't see why they wouldn't have another season. Highschool DxD had a new season just last year. Heaven's Lost Property is getting a movie later this year. I'm not sure about Highschool of the dead but if the sales are good enough and there's enough content, then why not? AoT is definitely getting another season but nothing has been confirmed. I'd say a season sometime this year or a 2-cour next year.