I have yet to find anything quite as nice as SSMS for Postgres, but Navicat for PostgreSQL is pretty good. It's not free, but its not expensive and has features

I have yet to find anything quite as nice as SSMS for Postgres, but Navicat for PostgreSQL is pretty good. It's not free, but its not expensive and has features I feel are worth paying for such as being able to diff schemas or data across DBs on different servers.