It's an e-card that, when scanned with an e-reader, reveals bonus content like mini-games or Pokdex info
Here are the 11 I run, from those I currently like most to least: Tatyova was the inspiration for me to add this package and she acts like the anchor card
In general, you should aim to play four copies of a card if: It's a vital part of your game plan You want to be able to consistently draw it It gets better in multiples If you've built your deck correctly, this should be the case for most cards you're running
Here is how the list breaks down by price tier, based on average TCGplayer market prices: Under $10 (Budget Game Changers) Gamble, Crop Rotation, Fierce Guardianship (from precon reprints), Narset Parter of Veils, Underworld Breach, Opposition Agent, Biorhythm, Coalition Victory, Braids Cabal Minion, Gifts Ungiven, Panoptic Mirror
These cards get around that
Geological Appraiser Another good piece of value for a Pia Nalaar, Consul of Revival, or as a part of the Faldorn, Dread Wolf Herald Commander deck