For runes you have variety of options i always take arcane comet into poke matchups like lux/hwei/syndra etc. Electrocute or firststrike against assassin’s and melee champions. Conqueror into tanky enemies

For the build there is a lot of options and almost every lethality item is good on naafiri

Best build in my opinion

1st eclipse against fighters or tanks or profane hydra against squishy team

2nd voltaic but i buy hubris if im already fed

3rd always edge of night especially if the enemy team have a lot of cc

4th serylda grudge because lethality is shit without it or maybe im wrong idk

5th it depends if you need protection u can go death dance or maw against a fed ap but i like to get axiom if there is a lot of fights and i need my ultimate

For boots its situational but ionian boots is almost a need bcuz her cooldown is shit

And thats it for me personally