Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Templates (template_type_code VARCHAR, Template_ID VARCHAR)
TABLE: CREATE TABLE Documents (template_ID VARCHAR)
TABLE: CREATE TABLE Ref_template_types (template_type_description VARCHAR, template_type_code VARCHAR)

### Question ###
What are the distinct template type descriptions for the templates ever used by any document?

### Accurate SQL ###

SELECT DISTINCT T1.template_type_description FROM Ref_template_types AS T1 JOIN Templates AS T2 ON T1.template_type_code = T2.template_type_code JOIN Documents AS T3 ON T2.Template_ID = T3.template_ID