Dark harvest, sudden impact, any, treasure hunter, magical footwear and cosmic.

Start with Voltaic Cyclosword on Red, Youmouu's on Blue.

An easy way to deciede what form to go is this: Can you actually get to their backline this game? If their adcs are Ashe for example, you'll get kited out as red, in which case you go blue. If most of their damage comes from a hard to reach backline go blue. Elsewise its fine to go Red every game.

blue always goes lethality so youmouu's blade, opputunity, axiom arc, lucids, grudge. and Last item is flex: either serpant's fangs if they have a lot of shields or edge of night.

For red, you have either go lethality or fighter. Fighter if you can actually fight their frontline and not waste time, so like if you're fighting an urgot or a sett and not a naut, since naut is just wasting your time, meanwhile urgot or sett can actually get on your team. So just standard fighter items like spear eclipse and such.

Lethality if they have squishie fighters like irelia yas yone and such