My ranking of the 5 Kages based on how much they contributed in their fight vs Madara
This is a strongest to weakest ranking, I'm only ranking the Kages based on how much contribution was made in fighting Madara. Anyways here's my list:
1. Onoki: Saved everyone from a meteor, destroyed Madara's Flower Pollen, broke A out of Genjutsu, destroyed nearly all of Madara's mouton clones and used his defense to protect everyone from Yasaka Magatama.
2. Tsunade: healed Onoki, healed Gaara, busted a hole through Susanoo, and used her medical ninjutsu to give Onoki enough strength for one last Jinton attack, plus she's probably about to heal the 5 Kages.
3. Gaara: Flew everyone in the air with his sand, protected Mei, helped block Yasaka Magatama and helped bind Madara in order to seal him.
4. Mei: Used Suiton Dragon to extinguish Madara's Katon attacks, used hidden mist to blind him, attacked him with lava, and helped almost seal him.
5. Raikage: he would have done better if his other arm was there I guess