Open source alternative to SQLMaestro for PostgreSQL
I found awesome tools in PostgreSQL wiki thank for your help guys.

The summary:


PGmodeler: If we mixed pgAdmin with PGmodeler we'll get full alternative to SQLMaestro for PostgreSQL but we'll miss one thing which is "Reverse Engineering" to the database because PGmodeler works in one direction.
As of 2017, importing existing schema / layout (aka. "Reverse Engineering") is possible with PGmodeler!
Power Architect: Supports many database engines but its designer has problem with database syncing "Forward Engineer" in case the developer changed the design of the scheme by another tool (ex. pgAdmin) in addition to slow performance in case of designing big schemes because it uses Java/Swing and finally, the user guide is totally commercial for 99$... damn :(
Open System Architect: Supports many database engines but it seems dead project although it built by Qt (latest commit was in 2010) I couldn't connect to any database because it failed to find unixODBC path although I already installed it in my Mint Linux!
TOra is also worth noting: TOra - An Oracle Toolkit for DBA's and developers. PostgreSQL support is officially not complete - seems to work reasonably well with older psql versions (&lt;= 9.4), while having a segfault now and then. Special: All SQL queries (used to fill the GUI with data) may be edited.


I wish this will be helpful to you.

UPDATE: As of 2017, importing existing schema / layout (aka. "Reverse Engineering") is possible with PGmodeler!