Add vector tile sources to QGIS

this plugin is still work in progress, and only works on Linux, but allows you to read mapbox vector tiles : https://github.com/geometalab/Vector-Tiles-Reader-QGIS-Plugin

The plugin mentioned above is now being develop from another developer and runs on Windows and Ubuntu. It's still experimental but a working version is expected in June.

Vector tiles are now supported directly in QGIS 3.14+:

https://www.qgis.org/en/site/forusers/visualchangelog314/index.html

https://www.lutraconsulting.co.uk/crowdfunding/vectortile-qgis/

QGIS 3.4 Answer

There is a plugin called: Vector Tiles Reader which can do this in QGIS 3.x:

Once added, it will be located Vector Vector Tiles Reader Add Vector Tiles Layer...:

And then you can provide your info and add the layer: