There is this theory, mainly developed by David Deutsch at Oxford, called Constructor Theory. I tickles my brain in all the right ways; It’s a fundamental theory of reality, but not reductionistic in the way that other fundamental theories in physics are (like quantum field theory). I think it can be best compared to the law of energy conservation, a type of meta-law.
The theory treats composition as a fundamental property of constructors and substrates, and I have a feeling it can be well formulated in the language of category theory, or a resource theory (even though Deutsch himself disagrees with this), and I am thinking about this off and on. There will most likely be a follow up post on this.
I was recently interviewed by Logan Chipkin who was writing an article for Gizmodo on constructor theory. You can find the article here. I think it gives a very good overview of the theory, its potential, and criticism, and can hopefully get more people excited.