The third card that youll find in every Legendary Collection 4 is Marik Ishtars Card of Last Will
However, the distribution of these does not mean you have a chance of getting 3 full art cards, no, it just means youll usually get two reverse-foil cards and then a holo-rare or sometimes a Pokmon ex or full art/ultra rare card instead
These days, there are more utility ways to "storm off" than building a board of goblins, but it's still one of the best ways to ramp in a goblin deck if one needs to get multiple spells cast on a single turn
For building this deck, you're going to want access to The Great Olds secret pack, which is one of the best ways to claim Exodia
Some details are locked up by Wizards, but theres enough info from the printing world and the MTG community to build a clear picture of whats going on under the art