Demon!OC. Katie tried to help Sam while Dean was trapped in hell, but Sam lost her too. When she comes back with a demonic upgrade, is she really on their side? Sam feels guilty over her death, Dean doesn't trust her an inch, and Castiel thinks she's an abomination. Will they really be able to stop the apocalypse? Castiel/OC.

Lyssa Devons was trying to run away. But a freak lightning storm sent her to another destination entirely - the TARDIS. Now she's being tossed around the Doctor's timeline, where everyone seems to know who she is. The trouble is, that she doesn't. What's worse is that something's following her - something that can transcend time and space. And only the Doctor can help.

I'll worship like a dog at the shrine of your lies. I'll tell you my sins and you can sharpen your knife. Offer me that deathless death. Good God, let me give you my life. Sherlock Holmes x OC

His mind was beautiful. It was wild and untamed by anyone, but him. People called him a freak, just because of his brilliance, but Victoria Radcliffe has never seen anything more thrilling. The chaos hidden in his piercing eyes was the biggest riddle out of them all. And she loved riddles more than anything.

I thought it was a dream. All of it. It was too good to be true, but now I have a choice to make. Do I go back? Do I save the man who's always saving others? Can I save the Doctor? "Oh Alexander. My Alexander. You managed to save one person... One big important person, hundreds of times over... and he doesn't even remember if he thanked you." 9-12 DoctorxOC (Classic Who later on)

Charlotte Williams is perfectly human, thank you very much. Well, she WAS perfectly human. Once. Sort of. Who would have thought her life would change so much after her best friend's work got blown up? Certainly not her. Adventure, around every corner and a discovery that would change who she was. Literally. Oc/9th Doctor (friendship) and eventual OC/10th, 11th, 12th, 13th Doctor.

the Doctor wasn't sure if he could possibly move on from losing Rose. That is until he met Alyssa Palmer, the granddaughter of Emma Grayling the empathic psychic. The gifted girl did what no one else could, healed him. (post season 2)