Query to check installed item types in SDL Web Content Manager database. This information can be used to determine if there are legacy items used. Also see https://gist.github.com/ea710455b86df711b5aea971ccd54b83
Installed item types
--------------------
Check with legacy item types are used. 
SELECT [ID]
      ,[SORT_ORDER]
      ,[TABLE_NAME]
      ,[NAME]
  FROM [Tridion_cm].[dbo].[ITEMTYPES]
  ORDER BY ID
Used Item types and sub types
-----------------------------
Check which item types are used and count them. This gives an general idea of technologies used, and specifically if legacy techologies like VBScript are used.
SELECT TOP 1000 [I].[ITEM_TYPE]
      ,[I].[SUB_TYPE]
      ,COUNT([I].[ID]) as COUNT
  FROM [Tridion_cm].[dbo].[ITEMS] I
  WHERE VERSION = (SELECT MAX(VERSION) FROM [Tridion_cm].[dbo].[ITEMS] I2 WHERE I2.PUBLICATION_ID = I.PUBLICATION_ID AND I2.ITEM_REFERENCE_ID = I.ITEM_REFERENCE_ID)
  GROUP BY [ITEM_TYPE], [SUB_TYPE]
  ORDER BY [I].[ITEM_TYPE], [I].[SUB_TYPE]