[SQLite]

I think (I hope!) we are probably done adding keywords to SQLite. Furthermore, all of the more recently added keywords (ex: WITHIN, RETURNING, MATERIALIZED) make use of special capabilities in SQLite's parser that allows keywords to be used as identifiers as long as the identifier usage does not occur in a context where the keyword is allowed.

So, for example, you can used MATERIALIZED as a keyword in a common-table expression ("WITH xyzzy(a,b) AS MATERIALIZED (...)") but MATERIALIZED can also be used as a column or table name. Hence, the following SQL actually works in SQLite:

   WITH xyz(MATERIALIZED) AS MATERIALIZED(
     VALUES(1),(2),(3)
   )
   SELECT * FROM xyz;