Xobni - Xobni provides effortless email and address book management and search for Microsoft Outlook and BlackBerry. Put a face to every name. Lightning fast Outlook Search.
Apache Solr - Solr is an open source enterprise search server based on Lucene search library, with XML/HTTP and...
Live Inbox - Live Inbox is a Microsoft Outlook plugin that helps you organize your email and search your inbox.
Websolr - Exterprise-grade search powered by open-source Apache Solr.
X1 Search - X1's Lightning-Fast Search Software. Premium Alternative to Windows Desktop and Outlook Search.
Decisiv Search - Decisiv is an enterprise search solution enabling users to search multiple repositories at once to access documents, projects etc.