One I've enjoyed in the past is the notion of a house with a sort of transformation field around it, whereas every living thing within the house has a sort of 'TF musical chairs' reset at the start of everyday, where everyone transforms into some other creature that exists in the house at the same time. Once you find yourself transformed, you'd be stuck there in the hopes that, eventually, you'd find yourself you again, or not...

Citras.

One of my favorite TF fantasies is taking a vacation from humanity. I'll often daydream what it would be like to ask a friend to watch my dog while I'm away for the week. I then transform into a dog and am picked up by my friend who has no clue he's really taking care of me. This vacation theme could work for other species too. You could plan to spend a week at a zoo or aquarium or even on photo safari in Africa as a lion.

When I was a child, I imagined turning into a dragon to help me deal with the fear of thunderstorms, of all things.

i usually sing when i am left with my thoughts and they all of the sudden turn dark ^^

I am the dude that loves the classics. A simple Werebeast transformation. it always makes me feel so full of power

Growing wings. It starts as an odd itch on your shoulder blades, where you can't quite touch. Then, once they're fully in, you have to work out a comfortable tucked position to keep them in. Then you shut your eyes and try to touch your nose with just the tip of one, then the other.

Being sucked into a show or game or movie of your choosing, to become one of the cast is usually nice and fun, depending on what it is. I like to imagine them coming out, and needing a vacation (or maybe a permanent vacation) and changing you into their doppelganger, mind and all, to take their place x3

Have you seen the 1992 film "Stay Tuned"? It's almost exactly what you said, and it even includes an animated segment that was done by Chuck Jones. The TV shows were sort of hellish/distorted versions of actual popular shows from the time, so i wouldn't call it "pleasant and anxiety free", but the idea of it was still pretty funny and cool.

I have never seen that, I would've been 2 at the time XD
Should look that up though ;3

Give it a try! The jokes/references might seem dated now, but it's worth a check.

Transformation itself that is anxiety-free would be an escape in and of itself. Likely reversible, possibly unexpected, yet universally welcomed.
How about a transformation that brings one into a sense of relaxation and belonging?

On a snorkeling trip in a tropical location when encountering wild dolphins, one soon feels comfortable swimming among the pod. Each dive below the surface takes less effort, and breaths are spaced further and further apart. The fluidity and motion of the cetaceans surrounding you is so beautiful and easy that as they brush their rubbery bodies along yours affectionately, you begin kicking both legs in unison more like they do. It doesn't take long to notice those legs are now bonded together, and that your skin no longer feels friction against the flow of water as it becomes smooth like theirs.

The shift in your body's form feels as natural and graceful as the motion of the creatures that surround you. They click and whistle playfully while watching you slip away from your terrestrial self; the hope of a new joyful member of their pod motivating them to nudge your transformation along with soft touches of their flippers and gentle nudges of their beaks. You pull your arms in against yourself instinctively, and feel them begin melting their way into you, save for your hands whose digits spread apart and reshape into the pectoral fins of a tursiops. As you surface for another breath, you realize your nose and throat have closed off from your lungs, but air still reaches them. The sensation is odd at first, but opening and closing your blowhole becomes second nature within only a few tries. You notice the water flowing along your belly is no longer reaching your genitals, since they have now disappeared into a smooth slit, hidden away within.

The swim trunks you wore have slipped away as your hips vanish in the streamlined torso of your new self. They cling to your flukes for a few moments before a flick of your tail sets them free to drift behind you. The stretching sensation upon your face doesn't feel like it's being pulled as much as it feels as though you've finally managed to relax yourself beyond the confines of your corporeal body. A long, firm rostrum protrudes and fills with conical teeth as your eyes adjust for the water, and the world around you becomes crystal clear.

Your vision, hearing and touch now amplified, you elegantly twirl your way into a roll and slide along the bodies of your new friends with a deep sense of belonging and appreciation for the gift you've been given. Your podmates accelerate, eliciting your desire to give chase, and amidst a chorus of shrill, melodic dolphin song you play, tumble, spin, leap, and bow. As the game dies down, the motion slows. The group coasts through the still, turquoise water together, with you now a welcome member. One particular dolphin which seemed to eye you closely the entire time approaches alongside, and gently touches her pectoral fin's tip to yours. The soft contact is without demands, wants, or even desires, save for one: Friendship.

Swimming along in perfect synchronization, the two of you glide through the sea with your pod into whatever adventures await you beneath the waves.

Perhaps it's guys becoming better-suited for their jobs...that could mean your basic stereotypical anthroization (ie, German Shepherd cop, rhino construction worker, owl security guard)...but it could also mean bits and pieces...i even had one where a guy's finger (index on his writing hand) became a pen. So if you're left to sit foe hours...perhaps as a security guard monitoring security cameras, a likely change could be melding with your chair - no need to get up - and possibly growth of other eyes/heads, to better monitor all those screens. And if you really want to get weird (who doesn't?), you could come over all rubbery, because everyone knows rubber animals don't need bathroom breaks

...think of it as job security

For a scenario suggestion, how about a possible series of pieces centered around an alien TF travel agency. Customers would come in, select a planet and species of their choosing, then get TF'd and transported to their vacation.