awesome-sql

List of tools and techniques for working with relational databases inspired by other awesome lists.

Oracle - Software and packages specifically for Oracle and PL/SQL.
SQL Server - Software and packages specifically for SQL Server and T-SQL.
MySQL - There is already a whole awesome list just for MySQL.
Cross Platform Stuff
- Formatters - Tools and sites that will format your ugly SQL code.
- Tools - Other cool tools and sites.

SQL Developer - Oracle's Free IDE for PL/SQL development and administration of Oracle databases
SQLcl - Free command line interface for Oracle Database.
SQL Tools for Oracle - Lightweight frontend for Oracle DB development.
Oracle Database Express Edition - Free entry level database to develop and deploy applications
Alexandria PL/SQL Utility Library - Collection of utility packages for PL/SQL
PLSQL-JSON - PL/SQL library to encode/decode JSON
utPLSQL - Unit testing framework for PL/SQL

SQL Server Express Edition - Free SQL Server Database to develop and deploy applications
SQL Server Data Tools - Integrated environment for developers to design and build database and other business intelligence solutions for MS SQL Server stack.
tSQLt - Unit testing framework for SQL Server
MSSqlCLI - A command-line client for SQL Server with auto-completion and syntax highlighting

Formatters

SQL Format - Instant SQL Formatter
Poor SQL - Instant Free and Open-Source T-SQL Formatting (look here for the plugins and whatnot: https://github.com/TaoK/PoorMansTSqlFormatter )
ExtendsClass - Online SQL formatter

PixQL - Command-line image processing tool in SQL by @Phildo
SQL Fiddle - Easly test and share database problems and their solutions. Can use different backend DBMS's (MySQL, PostgreSQL, MS SQL Server, Oracle, and SQLite)
SqlPad - A web app for running SQL queries and visualizing the results
ERAlchemy - ERAlchemy generates Entity Relation (ER) diagram from databases
BigBash - Open-source converter that generates a bash one-liner from an SQL Select query, no database necessary
Flyway - Database migration tool
Liquibase - Source Control for your database
Rumba RDBM - Database migration tool, plain-SQL, and declarative definition supported
PgCLI - Postgres CLI with autocompletion and syntax highlighting
LINQPad - LINQPad is not just for LINQ queries, but any C#/F#/VB expression, statement block or program.
SchemaSpy - we will do the best to simplify documentation process of your database
MissionKontrol - Self-hosted admin panel to manage one or more MySQL/PostGRES databases.

Curated SQL Learning Resources on Hackr.io - Programming Community Curated Resources for learning SQL