The 1955 Parkhurst Bronko Nagurski could certainly be considered for the list.
I did a search for recent sales on EBAY and The Undertaker mentioned above sold for $400 so that is certainly an important card.
While I personally have no real interest in the paper cards the 1973 Andre The Giant has commanded strong prices on a handful of occasions.
The WCW/NWO Hulk Hogan autograph is very popular and brings very strong prices. There are others from the set such as the Ric Flair that I have read have sold for big money.
The 1985 Topps Hulk Hogan is a card that certainly could be included on someone's list as it is the card that everyone who grew up in the 1980's remembers. That is the card I searched for in 2009 that made me aware of the 1982 Wrestling All Stars.