...as written about in 1993.
I was going thru some of my junk stuff this afternoon and found a bunch of old Beckett magazines. I found the 100th Anniversary issue from 1993 (which is really odd, I stopped buying cards in 1990 and my last Beckett was as such, I have no idea how I got this issue!) and found this article. Pretty cool...and I'd say I agree with a lot of the cards, and it is funny how time has changed in the last 20 years and some cards didn't pass the test of time. Here goes, and the comments are theirs, not mine, and they did mention this was NOT always a pricing issue, but it's "importance to the hobby" -
#1 1952 Topps Mickey Mantle
"The hobby's crown jewel of post war cards. Even copies graded at Fair to Poor draw a premium."
#2 1968 Topps Ryan/Koosman
"Even after his retirement, this card will remain a beauty."
#3 1963 Topps Pete Rose RC
"Among the first cards to boom from speculative interest..."
#4 1948 Leaf Babe Ruth
"The last card issued during his lifetime, it's also considered the Babe's final regular season issue."
#5 1954 Topps Hank Aaron RC
"We can think of 755 reasons to admire this card."
#6 1954 Bowman Ted Williams
"The most important variation among modern issue's...and that includes the Billy Ripken fiasco."
#7 1948 Leaf Joe DiMaggio
"Joe D's last regular issue cards."
#8 1951 Bowman Mickey Mantle RC
"We are talking about the true rookie card here."
#9 1984 Donruss Don Mattingly RC
"The Hitman remains the key card in a set that ushered in a new term into the hobby....scarcity."
#10 1955 Topps Roberto Clemente RC
"...and often difficult to find in top condition."
#11 1952 Topps Willie Mays
"The midrange number makes premium copies a rarity."
#12 1989 Upper Deck Ken Griffey Jr.
"The first card in a landmark set that many collectors believe ushered in the premium set era."
#13 1948 Leaf Jackie Robinson
"Jackie was a player."
#14 1951 Bowman Willie Mays RC
"This is Willie's only RC..."
#15 1984 Fleer Update Roger Clemens
"A tough, tough card of this generations best pitcher."
#16 1984 Fleer Update Kirby Puckett
"A tough, tough card..."
#17 1955 Topps Sandy Koufax RC
"This card offers collectors the first look at perhaps the games greatest lefty's."
#18 1967 Topps Tom Seaver RC
"...this is one tough high numbered card to secure..."
#19 1990 Leaf Frank Thomas
"Surprised? You shouldn't be!"
#20 1982 Topps Traded Cal Ripken Jr
"This is one of the first non rookie cards to surpass a previously released RC in value..."