One of the more scarce card issues of the 1970's was the Pino Ice Cream set from 1978. These were cards on thin laminated stock that were randomly inserted into boxes of "Pino Frozen Dessert Choco Ball". By randomly inserted I mean that only random boxes had a card in them at all - most boxes did not. Some of the cards were marked as "winner" cards and could be redeemed for a 3-D card.
I only have one card from this set - Kojiro Ikegaya of the Carp. Here's the front and back of the card: