A Top 25 list should consider the following factors:
The above factors do not alway fit together well.
In terms of sets (not individual cards!), I would suggest the following sets for starters: (not in any order!!!)
1949 Topps Magic Photo
1972, 1978, 1981 Magazine sets
1982/1983 Wrestling All Stars sets
1999 WCW/nWo Signature Series auto cards