If you specifically require version 10.0 for legacy compatibility, you can still find it bundled within Microsoft Feature Packs:
: If you have access to a SQL Server 2008 or 2008 R2 installation disk, the installer is located in the %CD%\Setup\ directory. Key Features and Compatibility sql server native client 10.0 download
Once you obtain the correct installer from a trusted legacy source: If you specifically require version 10
SQL Server Native Client 10.0 is an older driver primarily released with SQL Server 2008. It is no longer distributed as a standalone modern download and has been largely superseded by newer drivers, such as the Microsoft OLE DB Driver for SQL Server and the Microsoft ODBC Driver for SQL Server. sql server native client 10.0 download