Marian is my real name. I am a transsexual woman, went "full-time", as we say, in 1998, although I couldn't afford the surgery until 2010. I discovered Shifti via the TV Tropes page for Jon Buck's Paradise setting.
Growing up with gender dysphoria, I was attracted to transformation stories from a very young age. Especially TG ones. Some early favorites were Piers Anthony's Crewel Lye and John Varley's Steel Beach. I discovered the furry culture in the early 90s, and spent most of that decade hanging out on FurryMUCK and SPR as a snow leopard named Shaia.
Where the Tree Fails: this is a self-indulgent portal fantasy set in the world of the Dungeons & Dragons game. (Species)
Kissin' the Day: This was the first Paradise story I began writing, although it will probably be the last one finished, as it's the most personal. It's the only one to include a gender change. (Gender & Species)
Ratted Out: My second Paradise story. Skylar gets hit by the Change right before starting her freshman year of high school, and soon finds out who her real friends are. (Species)
Down the Rabbit Hole: My third Paradise story. This one looks at the Change from the outside, as Emily slowly discovers that the man she's dating isn't quite what he seems.... (Species)
Masks: After a magical artifact very publicly transforms him into a girl, Tyler has to adapt to the changes in her life--and so does everyone else. (Gender)
Future Tails: Romance between a mermaid and a human in a near future setting where biotech body modification is just beginning to become common.
Disclaimer: I have yet to read more than a fraction of the stories on Shifti, so if your story isn't here, it's not necessarily a comment on its quality.
Most the rest of the Paradise stories could also go on this list, but that would take too long, so I'll just call out a couple more that I especially like: Jetfire's Special Care and the sadly unfinished Coming Home by Nikon. I live in Ohio too and I've driven by Coon's Candy many times. Oh, and JonBuck's Family Tree. I absolutely died laughing at the LOLcat references.
Alveric's merfolk arc in the Xanadu shared universe: Hannah's Tale, Alex and Hannah, Wynd, Skye and One White Mouse, Mermaids of Xanadu, and Girl With the Sea-Green Eyes. After elves, mers are my second-favorite species.