If your code is popular, why not offer support to, or seek out sponsorship from, the companies that are using your modules/applications? A revenue-focused startup is probably a bad resource to tap for this. But getting a few companies to spread out a few hundred dollars each from their engineering/marketing budgets isn't completely unlikely.
Otherwise, you can always recite the age-old mantra to cleansing open source entitlement resentment: "Patches welcome."
Come to think of it, it's not even clear you could effectively write such a license for software (the analogous artistic license is generally about performance/broadcast, which doesn't have an equivalent in software). Once the user has received the code from the licensor, legally the situation is out of the licensor's hands _except for the issue of redistribution_, which is what the GPL restricts.
I'm honestly not sure what you wanted. You contributed code to something, and people used it. Some of those happened to make money on code that included yours (I'm sure the impact yours had on their bottom line is debatable). Did you expect financial compensation? Did you just hope for whatever reason that nobody would make any money off any code that you wrote? If you didn't want people to "avoid" your software, you wanted them to use it, right?
I occasionally write stuff for my own use that might be of use to others. There's no downside to me if I release it, and the occasional upside.
Sometimes I need to apply a fix to some OSS project. Contributing helps me avoid having to maintain a fork.
Sometimes I write something at work that may be useful for others and convince my employers to let me open source it, and as a result I am also able to reuse the same software at home or in future jobs.
None of these have deprived me of income. Some of the work I was paid for. Some of it has indirectly led to income.
I find your expression of resentment curious. Their use of your software did not deprive you of anything other than in your own mind.
OSS is freely given, sometimes by people who are paid to do exactly that. The term "unpaid labor" has a specific connotation akin to slavery or indentured servitude. The two are not comparable.
Complaining that someone somewhere makes money (at best, indirectly) from an OSS contribution is the same as complaining that Good Will resold my donation at a profit.
Is this a legal term of art or common knowledge definition? It was unknown to me so I've tried some googling and am turning up primarily volunteer work and unpaid internships under that title. I know wikipedia isn't the greatest source, but over there "unpaid work" is a class of things including both slavery and working at a family business or coop.
It has nothing to do with whatever political axe you have to grind.
It sounds a bit like you're buying a round of beers for everyone in the bar, and then you're upset people didn't compensate you for it.