On Charlie Calvert's Community Blog i found a where interesting list of LINQ Providers:

  • LINQ to CSV
  • LINQ to Amazon
  • LINQ to Active Directory
  • LINQ to Bindable Sources (SyncLINQ)
  • LINQ over C# project
  • LINQ to CRM
  • LINQ To Geo - Language Integrated Query for Geospatial Data
  • LINQ to Excel
  • LINQ to Expressions (MetaLinq)
  • LINQ Extender (Toolkit for building LINQ Providers)
  • LINQ to Flickr
  • LINQ to Google
  • LINQ to Indexes (LINQ and i40)
  • LINQ to IQueryable (Matt Warren on Providers)
  • LINQ to JSON
  • LINQ to LDAP
  • LINQ to NHibernate
  • LINQ to JavaScript
  • LINQ to LLBLGen Pro
  • LINQ to Lucene
  • LINQ to Metaweb(freebase)
  • LINQ to MySQL, Oracle and PostgreSql (DbLinq)
  • LINQ to NCover
  • LINQ to Opf3
  • LINQ to Parallel (PLINQ)
  • LINQ to RDF Files
  • LINQ to Sharepoint
  • LINQ to SimpleDB
  • LINQ to Streams
  • LINQ to WebQueries
  • LINQ to WMI
  • LINQ to XtraGrid