Momonosuke (if he dies the War ends, also saving onigashima from blowing)
Luffy (without him now there wouldn't be any chances of defeating Kaido, as It was said in the manga if Kaido would have been capable of reaching the live floor now they would all be dead)
Law/Kidd (Defeating a Yonko, nothing more to say. Without them Luffy wouldn't have been able to focus on Kaido)
Yamato (stalled Kaido, as I said before if this didn't happen then her father would have reached the live floor and murder everyone).
Zoro (protected Luffy, took the medicine, defeated a calamity, could be placed higher, especially if he stalls Evil Sanji :cheers:)
Sanji (saved Momonosuke, protected Luffy alongside Jinbe until rooftop, saved Zoro, defeated the Calamity Queen)
Marco (stalled Big Mom, stalled King and Queen until Zoro recovered)
Killer (helped Kidd, defeated Hawkins)
Robin (saved Sanji, defeated a Tobi roppo)
Jinbe (helped Luffy to reach rooftop alongside Sanji, defeated a Tobi roppo)
Chopper (for obvious reasons)