Okay, Substack hivemind! I need book swag ideas. My upcoming novel, The Jehovah Project, is a preapocalyptic philosophical thriller. As I start planning for the book release, what is fun swag?

So far, people have recommended stress balls with a skull pattern, and small sunscreens (Who cares about the apocalypse when you have SPF 50?).

There are also medical and tech aspects to the story. Hand sanitizer? USB drives loaded with an Easter egg?

All ideas welcome!