Docker Hub

Docker Hub is a repository for Docker images, that you can use to deploy into your Docker environment.  There are a bunch!

There are other repositories out there, but a lot of them feed back into the Docker Hub in one way or another.  You could also start developing or turning apps/code/etc into containers and pushing them up to the hub.  Me just saying that should give you an idea of how massive the Docker Hub is.

Explore The Hub
Docker Hub