Topps Pre-Production sets have quickly become a must-have component to my collections. As far as I can tell, they first started coming out around 1991 and continued through the mid-'00's. Topps Pre-Production sets typically consist of 9 cards, but I've also heard of 6-card and 3-card sets too. Currently, I have the Pre-Production sets for 1994, 1995, 1996, 1997, and 2002 Topps. The 1991-1993 sets consist of cards nearly identical to the base sets, but after that, variations start to show.
The 1996 Topps Pre-Production set consists of 9 completely different cards from the base set. Being the smallest Topps set since 1957, I welcome these 9 additions to my collection as variations. Actually, one of the cards--Rafael Bournigal--doesn't even have a '96T base card with the team provided.
1996 Topps #PP1 Cal Ripken
1996 Topps #PP2 Thomas Howard and #PP4 Ron Gant
1996 Topps #PP3 Rafael Bournigal and #PP9 Hideo Nomo
1996 Topps #PP5 Chipper Jones
1996 Topps #PP6 Frank Thomas
1996 Topps #PP7 Barry Bonds
1996 Topps #PP8 Fred McGriff