The best card? Probably the 1966 card with Bill Hands and Randy Hundley. Both were major contributors on the late '60s / early / '70s teams.
The worst? I'd go with the 1965 Ott/Warner card. Ott played in 32 games over two years and hit .222 while Warner had a 33 game career over four seasons and was 0-2 with an ERA of 5.10.
A couple had OK careers--Joe Niekro, Paul Popovich, Fred Norman, Billy Cowan, John Boccabella.
One of these guys didn't do well as a player, but became a successful coach--Billy Connors, who spent time as the Cubs pitching coach from 1982-1986 and 1992-1993.
The multi-year players....Fred Norman on 1964 and 1965....Dave Dowling on 1966 and 1967...John Boccabella, both 1964 and 1966....and Don Young, on both 1966 and 1969---a three year gap between cards.
And the duds? Just about all of them.