Trisha's Girl. A lonely young man gets to meet his favorite porn star in the flesh - but she's got a few surprises in store for him. He's going to star in her newest film, but to get him ready for the camera, she's going to have to make some changes. This is Male to BBW story that includes gender change, weight gain, and even pregnancy.
From Zero to Xena: The Ring of Change Saga. Shy, out of shape Zoe is attracted to her new personal trainer, but Jim could only love a protege student. Sparks fly when the power of the Ring of Change causes the student becomes the master - and even more changes occur when Jim puts the ring on as well. This is a female muscle growth transformation story.
And of course, check out my website if you haven't, which contains dozens of TF stories. I also do commissions, in case you are interested in that. Let me know what you think of these ebooks in the comments!