Across 1,520 ranked games on patch 16.21 in Master and above, Zeri mains win 54.1% of their games in the bot lane.
Their most common build appears in 53.5% of those games and wins 54.2% of its 813 games.
It starts 
two Health Potions and 
Doran's Bow, completes 
Yun Tal Wildarrows, 
Runaan's Hurricane, 
Infinity Edge and 
Lord Dominik's Regards in that order, and takes 
Gluttonous Greaves.
Two other builds are played often enough in the bot lane to be measured on their own.
In the bot lane, Zeri mains fare best against 
Yunara (won 65.8% of 73 games), 
Corki (won 81.8% of 11 games) and 
Jinx (won 61.7% of 60 games).
Their hardest matchups, the champions that counter Zeri, are 
Xayah (won 32.4% of 34 games), 
Vel'Koz (won 20.0% of 10 games) and 
Jhin (won 47.9% of 96 games).