ADC Senna is Broken AF (abuse before nerfs)

Runes:

Glacial Augment / Footwear / Biscuit / Approach Velocity // Manaflow / Celerity

Items:

Manamune / Boots of Swiftness (switch to tabis or merc treads late game) // Duskblade / Youmuus / Edge of Night / GA or Runaan's Hurricane (order to build the last 4 items could be flexible)

With Glacial Augment, her early game is kinda underwhelming; however, once you get some stacks and get your second item (lethality), you are literally unbeatable.

Building Crit items other than Runaans really don't benefit her as much since her crits are so weak. I tested that even with IE, her crit AA is only 1.38 times stronger than her non-crit AA.