At first blush, at least, Prototype has the hallmark of a solid keyword in that its reasonably simple to understand at a glance while simultaneously expanding the branches of your in-game decision tree in interesting ways
Second, youll notice this list starts with a lot of cards tied at the same cost
Tales of Middle Earth and Doctor Who have seen great success since, but Universes Beyond: Warhammer proved that MTG had the potential to deliver crossover sets that satisfied fans all around
For example, if you control ten permanents, lose control of one, then planeswalk to The Golden City of Orazca, you won't have the city's blessing
Altar of Bhaal Amethyst Dragon Animating Faerie Aquatic Alchemist Ardenvale Tactician Beanstalk Giant Beanstalk Wurm Bellowing Bruiser Beluna Grandsquall Beluna's Gatekeeper Besotted Knight Blessed Hippogriff Bonecrusher Giant Bramble Familiar Brazen Borrower Brightcap Badger Callous Sell-Sword Candlekeep Inspiration Chancellor of Tales Cheeky House-Mouse Colossal Badger Conceited Witch Cruel Somnophage Crystal Dragon Curious Pair Decadent Dragon Devouring Sugarmaw Dread Linnorm Edgewall Inn Edgewall Innkeeper Elusive Otter Embereth Shieldbreaker Emerald Dragon Ettercap Fae of Wishes Faerie Guidemother Fang Dragon Fell Horseman
Given how often that can happen in Tales of Middle-earth, Ringwraiths are basically a 5/5 body that your opponent can't get rid of short of exiling it