EdgeDB [1] has indeed a rich GraphQL layer, but it's a very different project.
While it also builds on top of Postgres, EdgeDB replaces the entire relational database front-end. EdgeDB features a SQL replacement language called EdgeQL (analytical capabilities of SQL married with deep-fetching in GraphQL), a higher-level data model (tables -> object types), integrated migrations engine, a custom protocol with great performance & great client APIs, and many other things. Read more here [2].
pg_graphql and EdgeDB both provide a graph-like query language on top of Postgres. EdgeDB
philosophically (I think) EdgeDB tries to do a more complete job of abstracting over Postgres. It has a custom query language (and GraphQL support via a plugin), and a migration system. Its runs separately from the DB.
In contrast, pg_graphql is more narrowly scoped. It enables you to query your existing Postgres database without caring how your data is structured or having any interactions with migrations. It also runs directly inside the database, so theres no separate process/server to manage.
While it also builds on top of Postgres, EdgeDB replaces the entire relational database front-end. EdgeDB features a SQL replacement language called EdgeQL (analytical capabilities of SQL married with deep-fetching in GraphQL), a higher-level data model (tables -> object types), integrated migrations engine, a custom protocol with great performance & great client APIs, and many other things. Read more here [2].
(disclaimer: I'm EdgeDB co-founder)
[1] https://github.com/edgedb/edgedb
[2] https://www.edgedb.com/blog/edgedb-1-0