he has explicitly denied the option for donations, which is excellent moral standing from my POV. However, it does beg the question - how can the community reward people who want to do this sort of work?

Perhaps a gigantic status of him standing over a harbor? Or a national holiday?

To be fair, the people who tirelessly maintain the filter lists should also be given accolades.

Accolades and money - Mr. Gorhill asks us to consider donating to the filter list maintainers instead if we want to give money to uBO.

Do you have a link or is this donating to each individual?

I guess each individual filter list; you can check your uBO settings to see which ones you use.