DBeaver - Universal Database Manager and SQL Client. DBeaver is free and open source universal database tool for developers and database administrators.
DBeaver vs PSequel opinions
DBeaver does the job well.
HeidiSQL is a useful tool designed for web developers using the popular MySQL server, Microsoft SQL databases and PostgreSQL. It enables you to browse and edit data, create and edit tables, views, procedures, triggers and scheduled events.
pgAdmin is the most popular and feature rich open source administration and development platform for PostgreSQL, the most advanced open source database in the world.
Open Source SQL Editor and Database Manager for MySQL, SQL Server, Postgres, Redshift, Sqlite and more.
SQuirreL SQL is an open-source Java SQL Client program that will allow you to view the structure of a JDBC compliant database, browse the data in tables, issue SQL commands etc.
Postage is a free PostgreSQL administration tool. It is as fast as any PostgreSQL interface can hope to be. Autocomplete pulls schema, table and column names semi-intelligently. Rich copy and paste functionality.This app doesn't have any features at the moment.Discontinued
As reported on the official website, Postage is no longer being maintained. Last version, 3.2.18, released in August 2017, can be still downloaded from GitHub