Correspondence Chess Game Collections in .pgn

Are there any large high quality correspondence game collections of high rated players that I can add to my SCID database?  

One of the largest databases for correspondence chess is the "Corr Database 2018" from Chessbase:

Corr Database 2018 (CBH)

With 1,4 Million games. Very good quality, but unfortunately it is not completely free...
Buy it, convert it to PGN with "Fritz", then load it to "SCID"

Another great source: ICCF (Archive) (PGN) (for free)

Have fun

 Much appreciated!  It looks like I have to register to the ICCF before I can access the archive, so I'm waiting on approval.  I'm hoping to skate by with free, if at all possible.

An interesting source (for free) for chess games is also the "KingBase":

KingBase

However, it has some limitations:
No annotated games.
No games with less than 6 moves.
No games before 1990.
No games with ELO-rating < 2000
Hmm... actually these are no "restrictions" at all... :-)

But important: They are not only correspondence chess games.
Nevertheless, there are certainly a lot of CC games among them.

Have fun

Yes, I have KIngbase and try to add to it periodically.  Sometimes I see a references to correspondence games that aren't in there.  It's a hole I wish to fill, especially for opening theory.  Again, thanks for your valuable input.