One side appears to be a sort of playable card game, but the back of the card is a holographic sticker with lots of random promotional art from the days of the original 151. These are RGB generation, possibly even pre-Yellow version and all art (on the front) is done by Ken Sugimori as far as I can tell.
Here is a shot of the front of one of the cards (featuring Vileplume and Eevee).
Instead of posting individual pics of all the cards, here's an icon post I made back in November that used all of the images of the cards I have. Anything ring a bell for anyone?
Does anyone have a clue about these cards?