Many of us have the same piece of information (for example employee number) stored in many tables. Often, different source systems have different metadata, in our example we have employeeid (varchar(10)) in the HR system, employeenumber varchar(255) in the ERP system, employeeid (varchar(50)) elsewhere in the ERP system etc.
It would be great if we TX supports alignment of the data types of these fields. For example through named custom data type aliases.
In the example above, we would define a data type alias employeenumber Nvarchar(10) and all the fields that we appoint this datatype will conform to it.
Before you know it this custom data type list will put you in the direction of a "canonical data model" as it has a similar purpose: to identify common concepts.
In this essence, the request can also be viewed as part of a search for more meaningful/functional metadata in general.