These are called room abilities. They can only be triggered as long as the dungeon is in play in the command zone and is controlled by the player who owns the dungeon
The total number of MTG cards depends on how you count them
The Fang of Critias The Fang of Critias Send 1 Trap from your hand or field to the GY, that is listed on a Fusion Monster that can only be Special Summoned with "The Fang of Critias" (if that card is Set, reveal it), then Special Summon that Fusion Monster from your Extra Deck
Of those 26 packs, and obviously ignoring promos that came in the various boxes, we got a total of six holo-pattern Energies, five ex cards, one Ace Spec, eight Pok Ball holo patterned cards, one Master Ball holo pattern, and four full-art trainers
(1) Target 1 monster in either GY