(It's an artifact with ", , Sacrifice this token: You gain 3 life.") Create a Treasure token
I checked over the list multiple times and I feel like the only two cards that don't synergize and I feel are a bit weak as generic filler is Pull from Tomorrow and Destroy Evil
Not only was the Charizard card a holo version also known as a shiny Charizard, which is considered to be one of the most popular cards on the collectors market it was also shadowless, meaning that a printing error had occurred in the making of the card, leading to there being no shadow behind the image of the Pokmon, making even rarer
However, since increasing deck size hampers your ability to actually find your key cards, it seems that it's only worth it for one-card combo kills and you should play lots of tutoring and filtering cards so you can find them faster
Batterskull, Basilisk Collar and Shadowspear have all created interesting opportunities for me in the past