I’ve got a setup on a server where I’ve got multiple users, each with their own database – a 1 to 1 mapping. By default, a login can see all databases in SQL Server Management Studio, even if they don’t have permissions to access them. Users are part of the public group so if you run the command:
DENY VIEW ANY DATABASE TO PUBLIC
Then users will only be able to see the database(s) for which they are an owner. I’m putting it here because I always forget this command.