Hi
I checked
as a repository for visualizations and dashboards.
Its content is ancient and small.
Where to find more recent and more diverse dashboards?
I'm not familiar with any, but I've asked in #kibana on irc to see if anyone else in the community knows of any good resources for this.
Hey, it was great for its time! 
How to encourage more people to share their projects?
Put it on GH and then post it here!
We are working on something to facilitate this, I am just not sure what the timeframe is.
We also have this - https://github.com/elastic/kibana/wiki/Known-Plugins