I'm pretty frustrated about this lately, I want to develop something out of the box, but all I see on the internet is the good old ToDo app or some clone. Please suggest some ideas I can start developing as a side project.

Edit - I got to thinking, and instead of going for a full-stack project, I thought of implementing a data structure Trie which I think is fairly complex; in JavaScript and by making an autocomplete feature with it. Tell me how you like this idea.