Herokuapp:
https://design-stories.herokuapp.com/ux-case-study-template
Built for mars:
https://builtformars.com/
Page:
https://page.co/Ry7jrn
UXfolio:
https://uxfol.io/
Muze:
https://muzedesign.com/spotify-case-study.html
Case study template:
https://www.figma.com/community/file/949395060452790372