This is by no means a definitive list, it's pretty much everyone I can remember off of the top of my head. If anyone else reads this or watches the anime let me know if I missed someone and I will rank them appropriately to the best of my ability. If you have any issues with the placement of certain characters feel free to let me know and see if we can come to a solution. I placed them in Tiers, Tier 1 being the strongest and Tier 6 being the weakest (albeit still around World Champion level, more or less) and I ranked them within each Tier based on feats, hype, martial arts skill, and various other things.
Edit: I added Yujiro and Yuichiro to a "Tier 0" because they are vastly above everyone else as of right now in the manga and it is only right to give them a Tier above the rest.
Tier 0
- Yujiro Hanma
- Yuichiro Hanma
Tier 1
- Miyamoto Musashi
- Pickle
Tier 2
- Kaioh Kaku
- Baki Hanma
Tier 3
- Izou Motobe
- Biscuit Oliva
- Kaioh Retsu
- Kaoru Hanayama
- Jack Hanma
Tier 4
- Gaia
- Che Guevara
- Orochi Katsumi
- Orochi Doppo
- Gouki Shibukawa
- Ron Shun Bun
- Kaku Shunsei
- Kaioh Ryu
Tier 5
- Muhammad Ali Jr.
- Speck
- Kaioh Dorian
- Amanai Yuu
- Andre Anov Garland
- Chiharu Shiba
- Zyaku Kaioh
- Yasha Ape
- Kureha Koushou
- Shinogi Kousho
- Kyosumi Katou
Tier 6
- Ian McGregor
- Yuri Chakovsky
- Yanagi Ryuukou
- Sikorski
- Hector Doyle
- Kanji Igari
- Mt. Toba
- General Strydum
- Atsushi Suedo
- Keechi Ando