Based on when they were/are shichibukai: Mihawk: holds the title as best swordsman in the world. former rivals with shanks(yonko). Strong enough to get bored (one punch man lol) Doflamingo: awakened DF, conqueror's haki, took two Super Supernovas (law, kid, luffy "super supernovas" cuz of 300million bounty at Saboady). Definitely one of the most dangerous, and only kept Shichibukai title for political reasons Kuma/PX-0: top revolutionary officer, cyborg enhancements and kizaru's laser, powerful DF, high speed Law: imo one of the most OP devil fruits, one of the top three supernovas, smart/analytical ***Was shichibukai post timeskip Hancock: conqueror's haki, highly regarded/feared for her strength (Navy/Rayleigh/Jinbe), honestly haven't seen DF powers to full extent (mainly used as fan-service/humor) Jinbe: Strongest fishman, master of fishman karate, probably top 3 when underwater Weevil: honestly hard to gauge power level due to ambiguity and scarce appearance, but probably strongest in terms of brute strength Blackbeard: "strongest" logia DF, did not have 2DF as shichibukai, honestly was more manipulative/sneaky and lucky than strong, definitely top3 post timeskip Crocodile: logia, extensive knowledge of DF ability-->good use of DF, still has high potential (possibly awaken DF?) Moriah: Honestly not that strong without shadows/zombie corpses. Also needs strong shadows for strong zombies Buggy: not counting his organization, good potential but doesn't live up to it, very lucky ***4-8 not a huge difference in power. Can pretty much be in one group. I think most people are overestimating Blackbeard, or they did not consider the "when they were a shichibukai" part.