The 1st missing card is actually a Superstars card depicting M.Mantle, W.Mays, and H.Killebrew #490. I decided organize the missing card with Mantle as the greatest superstar of the three players in my opinion. As you can see, I've also integrated the Game insert set into my collection as well. The rest of the players are organized by date of birth with multi-player cards fitting in according to the youngest player.
The 2nd missing card missing from my collection is Nolan Ryan's RC. In it's place right now is a 2003 Topps Shoebox Collection reprint card. Also included in my 1968 Topps collection is a custom Nolan Ryan rookie from the 2006 Topps Rookies of the Week set. I tend to integrate custom cards, and I really liked the '06T Rookies set.