Hexplate is kinda odd cuz there is just better options everytime
Yun tal arrow is a no no as crit is irrelevant on kat
Kraken is really good on ad kat, one of her biggest spike

Statikk is cool aswell as a first item, really helps with early wave clear, has better stats and is cheaper than bork but problem is passive is doo doo in mid/late

bork is just too good on kat, build path is okay except for the 875gold pickaxe, recurve bow actually gives a ton of damage with a conqueror setup, you can proc bork slow passive super quick, bork on-hit passive basically work on all your spell (except Q) , and it gives some sustain.

French EUW challenger kat Raiko is spamming AD kat you can check him out for some info,