Pieter Levels is a solo entrepreneur who makes roughly 2.7 million a year, largely from running Nomad List, but he runs several other businesses too.

https://nomadlist.com/

Other businesses he runs are listed in his Twitter bio:

https://mobile.twitter.com/levelsio

Here’s a recent interview:

https://m.youtube.com/watch?v=V0ej29G7ZGg