Certain cards will also gain oil counters, though these seem to function as a set-specific resource similar to energy from Kaladesh whose use differs depending on whats on the table
Static Pricing: Values fluctuate: recheck monthly for accuracy
The EX Pokemon were already going on for a while and kids knew they were really strong, but to have an even stronger version of that, I think that got a lot of people excited. 2
Even if that is not the case, players are unlikely to want a full stack of commons for one higher rarity card, unless they are seeking to make a very shiny flair
Plane - Ravnica Grixis Blue, black, and/or red creature cards in your graveyard have unearth
Don't stuff your deck with EX cards, instead, choose one or two and build your Pokmon deck around those cards