My favorite one is Dgraph
https://github.com/dgraph-io/dgraph
This is an excellent choice if you are looking for a rock solid scalable graph database.
Its written in Go, which for me is my language of choice for backend scalable fast solutions.
The community is helpful and available.
Plus it uses Badger for long term persistence.
Which is also a big bonus...
https://github.com/dgraph-io/badger
The combination of these two open source projects should definitely be reviewed by anyone considering a new project using graph databases...
One nice thing about Badger is that it is a tool similar to Rocks DB...
So Badger can be used standalone if you want a nice fast key / value DB written in Go as well.