There’s always the option for medical science, too. Universities and teaching hospitals still use cadavers for teaching and research. This is an option that’s a little more work than organ donation as there may be reasons why you’re unsuitable and like organ donation, it’s not just something that you can put in your will.
But if anyone is keen to give a med-student a hand (or a leg, liver, spleen etc.,) get in touch with the nearest major institution and not only save a life with your organs, but help save many lives with the other bits too.