We frequently use some datatypes like INT, CHAR, VARCHAR,etc. But there are currently 37 datatype supported by SQL Server. If you want to know the list of supported datatype, run the following methods
Method 1 : Use system stored procedure sp_datatype_info
exec sp_datatype_info
Method 2 : Use system table sys.types
select * from sys.types
There are other system stored procedures specific to each versions
Version 2005
exec sp_datatype_info_90
Version 2008
exec sp_datatype_info_100
Read more: Beyond Relational