Theres a huge difference in price between the original POP Series 5 Umbreon and the Celebrations one, though
The simplest answer is graveyard hate, with cards like Leyline of the Void, Rest in Peace, and Relic of Progenitus being among the best in the format at fighting Dredge and Surgical Extraction also offering a decent amount of value if you can get the timing right (exiling Narcomoeba or Bloodghast makes it hard for Prized Amalgam to return to the battlefield, while getting rid of Creeping Chill with the "exile" trigger on the stack will fizzle the damage)
Shaun, Father of Synths Shaun, Father of Synths, feels more like a Simic card than Izzet, but that adds to the intrigue
Its limited distribution and unique design make it one of the most unusual modern Pokmon grails
This game title was never released in the USA but now you can finally play the translated version
You are going to tap your Sergeant for a two-mana fetcher, and then tap that fetcher, for a three-mana fetcher, and so forth, until you win with 5-6 Rebels out