Just a week or two ago Tim Berners-Lee suggested that Nextcloud - now that it is fully compatible with Solid - may be the means by which Solid achieves much broader implementation. I can't find the reference today, but I think you'll find that approaching Solid via Nextcloud will answer a lot more of your questions. Good luck.
The main resource is https://solidproject.org/
That said, it's really focused on developers for now. There's a list of apps, but most of them are more of a proof-of-concept.
There is a long list of apps in various states of completeness on the new website. Many of them are just prototypes that no longer work, however, so it could certainly do with some cleaning up.
If you'd like to try a simple working app, try e.g. Notepod (I made it).