Most of what passes for cool ontology these days—when people dare to do it at all—is just a form of atomism. How do I mean?
An atom is something that can't be cut any further. We think of them as little shiny pingpong balls like the ones we saw in high school chemistry.
This kind of atomism is deemed uncool. So various substitutes are invented, which I find only to be “new and improved” versions of the same thing.
A process is an atom, just a lava-lampy one.
A string is an atom, just a sub-quantal one.
A quantum is an atom, just an indeterminate or “intra-active” one (to use Karen Barad's formula).
Atoms reign supreme, two and a half thousand years after Democritus.
Or drop matter and say that it's all made of mind, like Anaximander. If you change the names and substitute the latest findings for “water” and “fire” you pretty much get the pre-Socratics. It's about time humanists started telling scientists how to think again, as they seem to be defaulting to some quite old stereotypes.
In my opinion, Aristotle would still be able to take you down but there you go.
Which leaves object-oriented ontology. The only non-reductionist, non-atomic ontology on the market. And one that is a lot more Aristotle-proof than the regular ones.