Anything that enhances your insight for wisdom. Philosophy comes to mind. As it helps you think out of the box. The big 3 philosophers and stoics are a great

Anything that enhances your insight for wisdom. Philosophy comes to mind. As it helps you think out of the box. The big 3 philosophers and stoics are a great place to start. Explore the differences of western and eastern philosophies too once you get a taste for the west. You'll naturally come across mental models this way rather than have to read a farnam street blog on. https://plato.stanford.edu/ https://plato.stanford.edu/