In 2005, Saviors of Kamigawa , the final set in the Champions of Kamigawa block, would do a tweak on flip cards making a rare monocolor cycle that started as creatures and flipped into enchantments
While there are other planeswalkers that just immediately win the game with Doubling Season (like Nahiri, the Harbinger getting Emrakul, the Aeons Torn), Samut, the Tested offers several different ways of getting the job done by tutoring out Emrakul, the Aeons Torn and Xenagos, God of Revels directly, finding Nahiri, the Harbinger to find Emrakul, the Aeons Torn, or using an entirely different combo altogether like Restoration Angel and Kiki-Jiki, Mirror Breaker
There are 20 mythics in the set, and all of them have at least one variant, either Showcase or Extended Art, and no additional ones past that
World Breaker World Breaker is expensive, but its very powerful if you cast it