The Sivir build for ADC is Phantom Dancer, Statikk Shiv, and Navori Quickblades. This LoL Sivir guide for ADC at Platinum+ on 14.3 includes runes, items, skill order, and counters.
Sivir Counters
51.4%
(+0.7%)
49.5%
(+0.4%)
4.1%
(+0.5%)
1.1%
(+0.2%)
761
(+10)