Depends on your skills. Documentation is always useful. If you have language skills, translation of documentation or helping create language packs/translations.
That’s just off the top of my head. I’m sure if I thought about it, I could come up with more.
This is why I am dreading when my 2017 dumb TV dies. It’s really telling that dumb TVs, which should be cheaper to produce and sell, are either not available or very expensive (as in commercial displays). Really proves the point that the consumer is really the product.