The middleware lists at SQLSummit.com includes recent updates to the
list of .NET data providers.

List of ADO.NET data providers (48 listed)
http://www.sqlsummit.com/DataProv.htm

OLE DB providers
http://www.sqlsummit.com/oledbVen.htm

ODBC drivers and servers
http://www.sqlsummit.com/ODBCVend.htm

XQuery engines
http://www.sqlsummit.com/XQueryProv.htm

JDBC drivers and servers
http://www.sqlsummit.com/JDBCVend.htm

Simple multiple table design question
Dot Net 2.0 or SQL Server 2005 problem?
Typed Dataset event handling problem
TableAdapter Preserve Original Values on Update (no Accept Changes
Binary Serialization -- how to actually insert into database?