I am asking for something more general than GDPR. And I guess the worst case isn't what I am looking for either (since that would just be "fullest extent of the law").

I am trying to see what people would actually litigate over and from what I've read it seems like GDPR only applies to larger companies or pretty egregious behaviors.

I want to get a sense of the EXPECTED financial damage versus the cost of full compliance. This is just random side projects and it will take longer to understand the legalese than to code it!

For example I am sure people often misuse open-sourced licenses, forget to pay for rights to use images or fonts, forget to register at copyright office for DMCA safe harbor, etc. But the cost for all of these is not the same. Open source license misuse only matters once you get pretty big and get on their radar. But misusing a Getty Image has a 100% chance of being fined since they scan the web for unlicensed use.