I made a tool that allows you to find the mathematically correct build for any champion (also includes a Practice Tool simulation where you can attack any champ instead of a dummy) :
Champion Mastery Guide – League of Legends Support
LoL Mastery Chart: How to see your most-played champions, all the champions in league of legends - thirstymag.com
Champion Mastery - a statistical analysis of 1M+ games : r/leagueoflegends
Champion Mastery in Wild Rift – Wild Rift Beta Support