I wrote summer themed patterns for Petite Blythe over a year ago: Ombre Bathing Suit for Petite Blythe and Hairbands for Petite Blythe. Finally, they are written up for Petite fans.
Shop link: https://www.etsy.com/shop/BlytheKnits
The patterns are sold separately. The swim suit has dyeing tips and explanations. Coming soon is swim suits for Neo Blythe. I had a request through Ravelry. I'm working on several styles and fine tuning them. Hopefully I will have them ready by next week.