Here's a money maker for those with 3D printers: airless basketballs.

[shattered world]

If you've got a 3D printer, airless basketballs are not only a thing you can print, but they sell for a lot on sites like Etsy.

Here's a free model you can use. Don't even need to design it yourself. https://makerworld.com/en/models/141676-airless-basketball#profileId-1457871

These things are selling on Etsy for like $100 each. Not even kidding, look. https://www.etsy.com/listing/4473530470/willson-3d-printed-basketball-airless