Content for a portfolio

Hi,

I am getting back into instructional development/e-learning after 8+ years. I have taken online Articulate Rise classes and can't wait to start creating and looking for entry level/junior jobs however, I am told I am going to need a portfolio.

Does anyone have any advice where I can get content that I can use to create my  portfolio? I am guessing it would have to be corporate materials as many companies would want to look for those type of samples.

I also work F/T at another job (in an office) so if I were to take on a contract to build a portfolio it would have to be one that wouldn't require me communicating/working on it during the day.

Any advice would be so very much welcomed. 

Thanks!