I could never share the test cases I have as they are specific to the project and customer and under NDA etc.
Consider to host your portfolio either on GitHub or a blog/website. Depending on the content and what platform you want to look into learning. Perhaps consider to have the testcases aiming at
https://club.ministryoftesting.com/t/products-and-sites-to-practice-testing-on/1242
Perhaps one approach could be to share something technical, similar to this by @daniel.dainton