1. Ben Beckman
2. Marco
3. Lucky roo
4. Jozu
5. King
6. Yasopp
7.Queen
8. Vista
9. Shiryu
10. Katakuri
Ben : around 1.8B to 2B (strongest YC and first mate of a powerful crew)
Marco : around 1.8B to 2B (second strongest YC and actual leader (when he had the bounty) of a Yonko caliber army)
King : 1.4 to 1.49B : barbarian and really powerful but lower bounty than Luffy.
Roo : 1.4B
Queen : 1.32B
Jozu : 1.2
Katakuri : 1B05 (if I remember well)
Jack : 1B
Vista/Yassop : 950 M : rivals : both specialist and really powerful. But they are no psycho.
Shiryu case is hard : his yonko captain is only 2.2 but will quickly rise so I think Shiryu is close to 900 or 1b but don't really know but it will skyrocket soon.