My company (cloudron.io) provides an App Store for self-hosted apps. We have an app store listing page which has the description and screenshots of each app. https://cloudron.io/store/index.html if you want to take a look. But we have this only for apps that we have packaged/maintain.

That said, the layout of your site is very nice! How does one get new projects added to the list? (For example, we would like to have Cloudron itself listed there).