You can download SQL SERVER Product Samples through below URL.
You can download Latest SQL SERVER 2005 Samples from below URL.
http://msftdbprodsamples.codeplex.com/releases/view/4004
You can download Latest SQL SERVER 2008 Samples from below URL.
http://sqlserversamples.codeplex.com/releases/view/30803
Adventure Works Databases – 2012, 2008R2 and 2008
http://msftdbprodsamples.codeplex.com/releases/view/93587
Adventure Works 2014 Sample Databases
http://msftdbprodsamples.codeplex.com/releases/view/125550
Adventure Works and Samples for SQL SERVER 2016 CTP
https://www.microsoft.com/en-us/download/details.aspx?id=49502
Microsoft Contoso BI Demo Dataset for Retail Industry
http://www.microsoft.com/en-us/download/details.aspx?id=18279
SQL Skills 