My question is: Are there any resources for fake briefs to build an digital product (web or mobile app) upon it? Of course there is an option to write it by yourself, but I think it is more objective if someone did it for you. Creating rock solid boundries and constrains.

Requirements: It should appear realistic, that it could be build upon it a real product. It doesn't need to have header with authority, deadline, number of meetings etc, but it should give you good idea what the client wants from you. Then I will use design thinking and document the journey how I worked out on a solution. From initial research to interactive prototype.

My shallow search on google wasn't succesfull so maybe anyone knows any resources on this topic?