Curated list of data models and database schemas

Posted this site because I have been browsing Github for database design ideas, for applications similar to the one I am building. Without reinventing the wheel (or missing common use-cases), I have already come across lots of ideas I would not have thought of (especially ones which would help make the system more extensible in the future, because in general, I was looking at more mature projects, who have already been through a few schema redesigns)

Idea: I would like to see a site (similar to this) which lists common application domains, and lists relevant data models for each, along with use-case, ERDs with annotations, description of the intent. And, "Stackoverflow" style, it would be interesting to see models voted up, if they were particularly useful, extensible, and so on.

Example would be a "blog" use case, and then show the default data model for Wordpress, Drupal, or other popular applications. In each example, we could see a graphical ERD, with notes ("This M2M field allows us to keep all revisions of a blog post" or "Each blog post can have multiple categories").

Relatedly, having a Gist-like ERD tool which supports annotations & feedback would be helpful too, for realtime collaboration in IRC. Example: "I am designing an calendar event system for my application, which needs to support views like "Show me all events containing 'change requests of X type"; How would I model the tables & relations?"

If anyone has come across a tool like any of these, would love to hear about it!

Would be nice to have DDL for various databases included for each one. Fun time-killing resource, though.