Well they wouldn't really be 'hidden parameters' if they were out in plain sight right? Right? (crickets).
Anyway, hidden parameters won't be available through a show parameter or from v$parameter, but can be selected from several x$ks% tables. Below is a query from RedShoreTech that output's it nicely. I added several column formatting options at the top, and you can whateverother conditional statements relevant to your purpose at the end, e.g. adding 'AND a.ksppinm like '%latch%'.
set linesize 200
col parameter for a30
col "Session Value" for a8
col "Instance Value" for a16
SELECT a.ksppinm "Parameter",
b.ksppstvl "Session Value",
c.ksppstvl "Instance Value"
FROM x$ksppi a,
x$ksppcv b,
x$ksppsv c
WHERE a.indx = b.indx
AND a.indx = c.indx
AND a.ksppinm LIKE '/_%' escape '/'
/
