As far as I can see, the values available in Drill include:
In a draft of SQL standard SQL:2011 Part 11: Information and Definition Schemas (SQL/Schemata), the available values should be (source: SQL:201x (preliminary)):
Some common databases, which have implemented INFORMATION_SCHEMA.TABLES view, show "BASE TABLE" instead of "TABLE" and use " " instead of "_" as delimiter in the values of TABLE_TYPE:
DB2 for i5/OS
In conclusion, "TABLE" should be replaced by "BASE TABLE" and "SYSTEM_TABLE" by "SYSTEM TABLE" in INFORMATION_SCHEMA.TABLES.TABLE_TYPE.
Besides, the words in other existing or future values of TABLE_TYPE should also be delimited by " " instead of "_", for example, "GLOBAL TEMPORARY" instead of "GLOBAL_TEMPORARY".