Bleach

Accidental Love Affair 

After seeing the girl he loves with another girl, Renji finds comfort in an odd place. A bottle of sake and a night of passion later, he and Byakuya wake up with an unexpected problem...mpreg

https://www.fanfiction.net/s/6844097/1/Accidental-Love-Affair

The Mating Game 

Ichigo gave up on being a normal human years ago. Now he's about to find out just how far from normal he really is! Picks up after the Fullbringer arc and continues from there. Since I don't know what'll happen next I'm going my own way with what happens after the Quincy arc and there may be unintentional spoilers! This isn't intended to be an Mpreg story. However it is yaoi!

https://www.fanfiction.net/s/8704400/1/The-Mating-Game

Baby Boom 

It's five years later and things have somewhat settled down in the Seireitei. It's late Summer and the hard won peace is about to be shattered in the most delightful way! Sequel to The Mating Game. RenxIchi and KenxBya

https://www.fanfiction.net/s/9292935/1/Baby-Boom

Unplanned 

After only being with him once the unthinkable has happened. Now unable to think of a way out Renji has two choices: let him in, or run. Either way he will not give up the child. ByaRen MPREG

https://www.fanfiction.net/s/8870117/1/Unplanned