In order to destress, Princess Celestia takes a potion that allows her to briefly be a child again. Could Discord, Sombra, and Chrysalis possibly benefit from the same procedure?
Starlight Glimmer's plan to go back in time had backfired, and she turned herself into a foal and went back further than she intended. Now she has to find a way to return to her own time and into her adult body.
Daring Do was pushed her into a Fountain of Youth and was regressed into a foal. She then finds Ahuizotl (who was also regressed into a kitten). The two have to trek through the jungles of the Tenochtitlan Basin and find a way to turn back to adults
Mistakes can occur even when you're too advanced for your studies... Twilight learns just that when a magical mishap results in both of her pegasi friends becoming foals.
Rainbow Dash and some of the other recruits from the Wonderbolt Academy were regressed into toddlers. Now they have to relearn how to fly to escape the Daycare and find Twilight.
(An indirect sequel to "Finding Shining" and "Finding Sunburst" by Foal Star.) Princess Cadence willingly turns herself into a foal to spend time with her daughter. But Cadence soon desires to have her own foalish adventure and slips away.
Dr.Whooves's time machine malfunctions causing him to regress into a foal and now has to go on a journey through time and space to turn back to normal.
(Story idea requested by superfun. Contains age regression, diapers, and diaper useage! Reader discretion is advised.) When Diamond Tiara and Silver Spoon lose a bet to the CMC, they are turned into foals for a week. The CMC must care for them.
(A collab with Latecomer, open to all authors. Stories should be SFW with some potential PG content, rated Teen to be safe.) A collection of stories involving various characters undergoing potty training, to varying results.