As of 2022, 54 countries had implemented special taxes on sugary drinks and/or sugar in general: https://www.obesityevidencehub.org.au/collections/prevention/countries-that-have-implemented-taxes-on-sugar-sweetened-beverages-ssbs
In many cases that covers sweets, snacks, etc. as well. Food is usually quite heavily regulated (in the sense that there's lots of regulation, not that it's actually strict or as much as it should be), even if it's not immediately obvious to us as consumers. E.g. there are ingredients that get banned because of being addictive or having certain harmful effects.
Porn is age gated worldwide, and in some cases censored. I'd class that as regulated pretty much all over the world, regardless of how hard/easy it is to circumvent the regulations (e.g. for a 17-year-old to access a porn website).
I think that actually covers all of the items in the list!
But then also many people don't have credit cards - they're frowned upon in many countries with a more debt-averse culture.
Whatever the solution is, it seems like it would end up being something country-specific and not something that scales well across the internet. Probably credit cards work for the US, but then we'd need to find something that works for the remaining 95% of the world population.