Some are rare, others just usually more than I want to pay...
T202 Tinker Evers Chance SGC 50
T207 Ward Miller (SGC anything)
Tie for third: T205 McGraw in SGC 60, 1934 Goudey Greenberg in SGC 60 or better
Modern:
1979 Topps Ozzie Smith in strong PSA 9
1948 Leaf Stan Musial in SGC 80 or better
Hages Dairy Handley cards (not terribly condition sensitive)