Here is described ways of opening different types of data sources using Open Data Source dialog, and important notes you should know when doing this.
If you cannot find the type of your data source here, you still may try to open it using description of similar data source type, using ODBC (if ODBC driver for your data source type exists), or using your own connection string (there are lot of connection strings' examples in the Internet).
Microsoft Access databases (.mdb)
Microsoft Access 2007+ databases (.accdb)
Microsoft Excel workbooks (.xls)
Microsoft Excel 2007+ workbooks (.xlsx, .xlsb, .xlsm)
Visual FoxPro databases (.dbc)
Text and CSV files (.txt, .csv)
SQL Anywhere (Adaptive Server Anywhere)
Exportizer can also open other types of databases, if the corresponding OLE DB provider or ODBC driver has been installed on your computer. You just need to build the connection string using examples from the internet.