Its ability looks pretty insignificant at first but combined with certain cards, it can help you produce infinite mana, buff your creatures with a gazillion counters and draw at the same time, or even have infinite turns
"I would say that the 1st Edition Fossil cards were much more accessible than Base [cards] and probably [were distributed in quantities] on par with Jungle," said Pratte
Thus far I've got some of the "obvious" cards: Daring Sleuth Flip , Beast Within, Pale Moon , Decimator of the Provinces, and Emrakul, the Promised End, but I'm at a loss for what else to include
Newer generations have a different set of grails, and their collective demand can make a modern card with a high population more sought-after than a technically rarer vintage card that doesn't have the same emotional resonance for them
When Aether Herder enters the battlefield, you get two energy counters