Which components of Microsoft SQL Server 2016 require a license?

The following components of Microsoft SQL Server 2016 require a license:

• SQL Server Database Engine (DB)
• SQL Server R Services for Windows
• Master Data Services (MDS)
• Analysis Services (AS)
• Integration Services (IS)
• Reporting Services (RS)
• Data Quality Services (DQS)

The following components and documentation do not require a license and can generally be distributed:

• SQL Server Management Studio
• SQL Server Configuration Manager
• SQL Server Profiler
• Database Engine Tuning Advisor
• Data Quality Client
• SQL Server Data Tools
• Software Development Kits/SDK (bspw. Clienttools SDK)
• Distributed Client
• Connectivity Components (bspw. Client Tools Connectivity)
• Software Add-Ins (for example Reporting Services Add-In for Sharepoint)
• SQL Server Books Online

Sources:

Microsoft SQL Server Licensing Guide, as is 2016-08-28
Microsoft Product Terms August 2017