The Khronos group has released a first version of a glTF importer/exporter add-on for Blender. This will make interchanging assets with other 3D apps such as Unity much easier. Sketchfab also offers all Creative-Commons licensed downloadable models as glTF (although you can also try the new Sketchfab importer).
A new Blender glTF importer and exporter is under development. The main features are:
- Importer and exporter functionality in one add-on
- Basic Principled BSDF cycles node tree import and export
- Support for Blender version 2.79 and 2.80 (WIP)
The Blender glTF importer and exporter is already functional and improvements are still ongoing.