Wizards of the coast released a life counter that was pretty cool, but also only available with the Commander deck anothlogies, thus making them unreasonably expensive on the secondary market.
An early iteration of the design without the spring mechanism
This design is free, download and print as many as you want! Just don't make a massive profit off them without throwing my name out there first ;)
The first 2 variables (excluding $fn, I'd leave that alone, that effects print quality) are what drive the entire model. If you want a really tall and thin life counter, change it to:
wheelWidth = 2;
wheelDia = 500;
but that would be terrible. After numerous tests and failed prints, I'd really say that:
wheelWidth = 10;
wheelDia = 30;
is the optimum size for the life counter.
A special thank you to user u/Efarm12 on reddit, who helped me with some of the more complex mathematical functions (the spring and the consistent rotation of the number).