The list is missing <a href="http://use-the-index-luke.com" rel="nofollow">http://use-the-index-luke.com</a> and <a href="http://modern-sql.com" rel="nofollow">http://modern-sql.com</a> which are some of the very best resources out there for SQL in general.
It also misses <a href="https://www.pgexercises.com" rel="nofollow">https://www.pgexercises.com</a> which is an amazing resource for learning the specifics of PostgreSQL in particular.