fairly certain top tiers end of series
imu
6 gorosei (1 inactive)
4 admirals
coby
aokiji
mihawk
shanks
shamrock
BB
loki
Law
luffy
zoro
sanji
dragon
sabo
wildcards
kidd
a few of the seraphim
That's over 20
For every Law or Kidd, there are 10 more Hawkins, Drakes, Apoos (character's you can barely even call high tiers) etc. The thing is we get to see the top tiers, but they are extremely rare. Most factions top out at 1, this is why BB pirates already have a major advantage, just by having Kuzan added to their ranks they are automatically the strongest pirate crew out there. It goes to show you how rare it is.
The Pirate King's crew was an exception in the past, and will be the exception today. I don't want to sound like a broken record but again, look at giants outside of Loki, look at the entire land of Wano, look at Zou. We just don't care for the Karasu's, Morley's of the world and like to focus on the Dragon's, for every Dragon there are like 100 named characters that are virtually fodder.
I actually think Oda is sometimes too conservative with top tiers, just look at CP0, Lucci is a beast, but that is by far the best they have, and he's not sniffing top tier status. We just got past the Yonkou saga, and Oda refuses to make the Holy Knights anything more than commander lvl and that might be generous for some of them. What he does instead is he gives them a link to Imu which makes them tricky and hard to kill.
And doesn't this community always complain that Blackbeard pirates are all fodder? How does that work if he's willing to hand out top tier status too easily? There's a reason there is a meme in the community where every new character that gets introduced we theorize they are Admiral lvl or above, and it always falls flat. Oda is very selective. Heck people have this valid complaint that none of Luffy's agemate/rivals are even close to him in power. In the Worst Generation only Luffy has reached that status outside of Teach. That just shows you how selective Oda is.