Open DBDiff - A database comparison tool for Microsoft SQL Server 2005+ that reports schema differences and...
gitSQL - Database source control for SQL Server, PostgreSQL
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
Flyway - Flyway is a database migration tool.
MssqlMerge - MssqlMerge is an easy to use diff & merge tool for Microsoft SQL Server databases.
Liquibase - Database schema change management and release automation solution.