Sample datasets for every supported data format are available for download from the yt Hub in the ytree data collection. The entire collection (about 358 MB) can be downloaded via the yt Hub's web interface by clicking on "Actions" drop-down menu on the far right and selecting "Download collection." It can also be downloaded through the girder-client interface:
$ pip install girder-client
$ girder-cli --api-url https://girder.hub.yt/api/v1 download 59835a1ee2a67400016a2cda ytree_data