LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC
DBConvert Studio - Database migration/ sync software for data conversion and replication.
My Visual Database - Using My Visual Database, you can create databases for invoicing, inventory, CRM, or any specific purpose.
Full Convert - Full Convert is industry standard for database migration. Supports 40 database formats and offers unparalleled speed and customization.
Kexi - Kexi | Calligra Suite
ESF Database Migration Toolkit - ESF Database Migration Toolkit enables transfer of data between various database formats without writing any scripts.