Autocomplete/Intellisense for For Columns in PGAdmin III
pgAdmin 4 seems to autocomplete columns when using dot notation. So hitting Ctrl+Space after
select * from table1 where table1.
will list all available columns.
If you like intellisense and other sweet features (as me) you can try to use "SQL Manager Lite for PostgreSQL", it is free. I use both (SQL Manager Lite hasn't queries-graphbuilder )
currently available for windows only