Login failed for user - Error 18456 - Severity 14, State 38 Message that SQL Server Log File Viewer shows: 

Login failed for user [User]
Error: 18456, Severity: 14, State 38


What it actually means:

Failed to open the explicitly specified database


My Question:

Is there a list somewhere of all the variations of the 18456 errors (Login failed), for each combination of severity and state, with the helpful description text?

I've had a Google but can't find anything other than specific combinations.
State codes and their meaning.
1      'Account is locked out'
2      'User id is not valid'
3-4    'Undocumented'
5      'User id is not valid'
6      'Undocumented'
7      'The login being used is disabled'
8      'Incorrect password'
9      'Invalid password'
10     'Related to a SQL login being bound to Windows domain password policy enforcement.
        See KB925744.'
11-12  'Login valid but server access failed'
16     'Login valid, but not permissioned to use the target database'
18     'Password expired'
27     'Initial database could not be found'
38     'Login valid but database unavailable (or login not permissioned)'

More detailed information is available in Aaron Bertrand's blog.
To find the status code, you need to inspect the SQL Server Error Log after ensuring that failed logins are recorded in the error log.