Under the new UK law, just adopted a few days ago (see here) an employee can surrender certain employment rights (eg, related to unfair dismissal, flexible working) and in exchange get shares of its company that have a market value of not less than GBP 2000. This has been highly controversial: e.g., critics saying that this “encourages employees to trade their rights as if they were commodities, frustrating their purpose as essential protections for employees”.
Of course, this is not really a commodification of rights since employees “just” get shares. But one could also imagine a real commodification similar to carbon emission certificates: here, say, all employees of companies with publicly listed shares would get certificates incorporating their employment rights which can also be traded on the exchanges where those companies are listed (ie these rights become securitised). Then, employees could sell these certificates, or if they want to, buy them back later on; also, being securitised, the price of the certificates would change depending on the current value of the employment rights (eg, depending on the risk of being made redundant). And to go one step further, why stop with employment rights: eg, one could extend it to consumer protection rights - most people may want to keep them, but if you need some cash, securitise them and sell them on an exchange until you may have the resources to buy them back.
Finally, of course, I don't think that any of this is necessarily "good" from a normative perspective - while it does seem to me an interesting model to compensate for opting-out of default rules (of course, just for the sake of the argument, assuming that these rules should really not be mandatory ones).