What happen to these shows?
high school DxD, Seraph of the End: Vampire Reign, Aesthetica of a Rogue Hero,
World Break: Aria of Curse for a Holy Swordsman, Absolute Duo,
They are over, for now at least (I know Seraph is coming back this Fall; I'm not sure about the others but someone more "in the know" might have some info).
Rogue Hero, Duo and World Break all had poor sales in Japan. It's unlikely they will have a another season. Nothing on DxD right now, gotta wait and see how it does in Japan.
Seraph comes back in the fall, and while High School DxD has yet to be confirmed for a 4th season, that show seems to have enough popularity and demand that they'll probably make another season once they get some more source material to work with.
The other three: World Break, Absolute Duo and Aesthetica of a Rogue Hero are all probably one and done shows. Usually people make a season to promote the source material and typically they don't always pan out in popularity and demand to warrant new seasons.