My current thing is Gaia Sky (github repo), a 3D Universe kind of thing focused on [ESA's Gaia](https://en.wikipedia.org/wiki/Gaia_(spacecraft\)) data. The current public release contains the Solar System plus more than 600K stars from the TGAS part of Gaia Data Release 1. Next year, with Gaia Data Release 2, we'll be in the hundreds of millions camp.
Yes, you can already access the first data release : https://gea.esac.esa.int/archive/. But you will have to make your own simulation. However, if you go to the web page of our colleagues in Heidelberg you can also get a 3D simulation :https://zah.uni-heidelberg.de/gaia/outreach/gaiasky/. [ES]