Dungeons can be accessed when a card has the phrase Venture into the dungeon on it, and has you journeying through different iconic D&D dungeons: Tomb of Annihilation, Dungeon of the Mad Mage and the Lost Mine of Phandelver
I dont have any concrete evidence to disprove the number 50 however, as anecdotal as it is Ive seen far too many for sale and know some collectors who also own them, to have only 50 wouldnt be realistic
Must first be Special Summoned (from your hand) by banishing 1 "Alpha The Electromagnet Warrior", "Beta The Electromagnet Warrior", and "Gamma The Electromagnet Warrior" from your hand, Graveyard, and/or face-up from your Monster Zone
Boros Charm: the best charm in Return to Ravnica block
BCW offers three varieties of Inner Sleeves: Regular Inner Sleeves are top loading, but a better description might be bottom loading
This essentially adds double the amount of content to the game because you're using an entirely different deck of cards