A series of seven books where 11 ended up in in a different dimension. He becomes the new astronomy teacher and goes with Harry on his adventures (actually he just follows them without their permission finding his own genius way around obstacle) This book is the scorcerer's stone. Enjoy.

Harry Potter comes back for a new year of Hogwarts for his 5th year. The new Astronomy teacher, Professor Noble and the Defense Against The Dark Arts teacher, Professor Smith, are unlike any Wizard Harry has ever met. When Harry discovers that Professor Smith isn't what everyone thinks he is, and what he almost did to Harry Potter last year at The Triwizard Tournament...

As a rule, England didn't hate his citizens. They might annoy him at times, frustrate him, drive him up a wall, but they were still his. In his history, there had only been a few exceptions. And now, there were five. So when Harry got his first letter to Hogwarts, England resolved to be there for him. England goes to Hogwarts! (only one I'm doing, unfortunately)

The Doctor and Rose are mysteriously pulled into another universe where magic exists.

The Doctor and Rose meet a very strange child who has white hair, purple eyes, and heals instantly. And the planet of origin is...earth? What's going on? You can read this even if you're not a Hetalia fan.

The Avengers and the countries — unknowingly on the same three-hour plane flight. Everything rapidly dwindles into chaos. One-shot.

When a kidnapped Tony DiNozzo is rescued by legendary - and supposedly dead - serial killers Dean and Sam Winchester, the NCIS team takes over the Winchester investigation. What they find is a file filled with contradictions and impossibilities. This is an attempt to cross these shows but keep both in canon. No slash. No pairings.

River comes across a story of an ancient warrior-sighted since the 14th century-known as the Demon of War. But as she and The Doctor investigate they find the 'demon' is far more human than one might think...