You are not looking hard enough!

But maybe you should find an open source project you like and see how you can start contributing in a meaningful way (meaningful to you).

Baring that, THINK SMALL. Think about one tiny thing to make, and then code the hell out of it:

- documentation - build process - tests - cross platform-ness - packaged for distribution (deb, Rpm, pip, npm, whatever)

I say all of this because a side project is often so much more than just the thing you want to code. Most of us devs would like to share our work, and the things listed above help other devs see that this project is serious and warrants our time / effort.