I'm prettty sure this isn't a feature yet, but on databases with large number of tables the ERD feature is not very useful without being able to select specific tables to show.
I'm coming from TablePlus, where you're able to manipulate the diagram by adding only tables you're interested in, like #122 add or remove relationships, and even add tables that don't exist yet.
It'd be great to have these features, but only being able to filter what tables to show in the ERD view would be very useful.
This is how TablePlus does it