Is there a lambda layer repository? Or are there AWS-provided layers?

I remember from the keynote that one practical use for layers is that you could potentially use layers developed by other parties. I was wondering, is there some kind of repository available where you can import an existing layer?

For example, in the case of Java, it would be nice if Amazon provides its own SDK as a layer, so that you don't have to use the shade plug-in to make a fat jar. Does this already exist somewhere?

It's not necessarily a lot of work to make, but if it's maintained centrally, that would be nice...