Sam Walton was estimated to be worth $8-25 billion when he died in 92'. After transferring 80% of Walmart stock ownership to his children.
Interesting stat on Walmart:
Walmart is estimated to make up 2.5% of US GDP.
Here are plenty of others:
30 Celebrities Who Have Reached Billionaire Status, Including Taylor Swift and Beyoncé
https://share.google/qCGxmx0dIWiSVgIgZ
There is much to argue wether they actually earned that money with their own hands, but their Names are on the letterhead and they pay the taxes.