Here is a brief list of my favorite pet names I may have used for a significant other at one time or another. I hope that you are inspired to use one or more of them.
But to start, let me help set the mood for you:
I apologize that some of these are coming from a male-to-female perspective, but many can go both ways.
-Cherry Pie (unoriginal, I know, STFU)
-All Mine :)
Good luck ladies and gentlemen, go forth and love.
* denotes a term I used in real life with repercussions ranging from minor to severe
+ denotes a term you should use with caution and only under the correct circumstances