Adam Milligan~

Sunshine: Because seeing you is the highlight of his day, and he thinks that it's cute when you get all flustered from him calling you that.
Eve: Because of Adam and Eve from the stories. He loves to boast to his friends that you were made in heaven just for him.

Balthazer~

Love.
He gave you the nickname love, because you are the love of his life.

Bobby Singer~

Honey.
You love baking sweets, and he is your preferred taste tester. You once had a food fight with him, and got covered in honey, leading to him teasing you with the nickname honey.

Castiel~

Honeybee.
You're his precious little honeybee, and he would do anything to keep you safe.
Dean gave him the idea for honeybee because he's not very good at the whole nickname thing.

Crowley~

My Queen.
He fully intends to make you his queen one day, and has taken to calling you his queen.

Dean Winchester~

Babe.
He would call you baby, but he can only have one baby, and that's his car.

Gabriel~

Sugar.
You're sweet as sugar in his opinion, and he thinks your lips taste like sugar.

Lucifer~

Darling.
He loves simpler things, and gave you the nickname darling, because it's simple and you love it.

Sam Winchester~

Baby.
You are his baby, ridiculously small compared to his 6,4 frame. He loves to hold you bridal style and tease you about being his little baby.