How many rulers did they have after Liu Bang's death? Were they more successful?

Do you mean the rulers of the Han Dynasty? Well, there are 14 emperors of Han after his death. He is the founder of Han. I think his contribution should be the greatest. The second successful ruler must be Liu Che. He implemented many moves to make Han prosperous than ever, such as openning up the Silk Road, driving away the Huns, and expanding the territory.