Some cards like Flash were banned specifically because of their effects in cEDH, although most of the cards are banned because of their effects on the format in general
It just so happens that in Hour of Devastation , the U/R archetype has a variety of one- and two-mana cards that scale well into the late-game
These cards are sought after by collectors especially in good condition and from iconic sets
Now that our spotlight series has moved through the first nine sets of this block ( Sun & Moon base, Guardians Rising, Burning Shadows, Crimson Invasion, Ultra Prism, Shining Legends, Forbidden Light , Celestial Storm , and Dragon Majesty ), it is now time to look at the next set from this era: Sun & Moon Lost Thunder
Imagine it is my opponents combat
There are also Ghostly Flicker loops to constantly blink lands as a way to generate infinite mana