By far my favorite set of all time the 1972 cards look like they should be in a episode of Cheers.
1973's I love the little silhouetted position player on the card fronts.
1974's very yin/yany. The arrows point you in the right direction.
Ah and the iconic 1975 Topps. I love the random color schemes. Not a bad haul for under 5 bucks.