Toad for Oracle - Toad is an industry-standard tool for application development.
Open DBDiff - A database comparison tool for Microsoft SQL Server 2005+ that reports schema differences and...
phpMyAdmin - phpMyAdmin is a tool written in PHP intended to handle the administration of MySQL over the Web.
Redgate SQL Data Compare - Use Redgate SQL Data Compare to compare and synchronize static, lookup, and reference data in your SQL Server database - try it free
SQL Developer - Oracle SQL Developer is a free, development environment that simplifies the management of Oracle Database in both traditional and Cloud deployments.
a7 SqlTools - Tools for MS Sql management with search, explore and comparison functionality.