Cook mix and stir thermodynamic synthesis
Pretty much all of today's natural chemistry and human performed chemistry.
The complement to mechanosynthesis / mechanochemistry and in particular force applying mechanosynthesis
which allows to access stuctures that are strongly metastable but are hard or not at all reachable via other means.
Including checkerboard compounds here aka neo polymorphs, See: Pseudo phase diagram.
Side-note: Point is not to acess almost all structures permittable by physical law
(most of them are not just metasabel but also not very metastable at that)
but to accessa ved novel ones as the basis for mechanical metamatwerials.
"cook mix and stirr themodynamic synthesis" is what humans are doing mostly so far (2025).
Chemistry happening in the wild (geologic processes, life processes, and in outer space processes)
makes for the subset of natural chemsirty which mostly overlaps.
So unnatural chemistry mostly covers mechanosynthesis and
maybe some other exotic processes that for some reasons or others can't happen in nature.