Spurred by the SEP entry on Quantum Field Theory by Meinard Kuhlmann, I spent some time attempting to draft a blog post about the philosophically problematic ontology of quantum particles and fields (see especially section 5 of the article). I decided I needed to read more on the topic before going further, however (I'd be grateful for recommendations for further reading). In reflecting on Quantum Mechanics itself, I’ve argued the merits of a dual ontology, where interaction/measurement events comprise the concrete macro-world, and the wave function provides a description of a system's natural propensities -- still “real” in an important sense, but not concrete.
But I don’t know enough at this point to flesh this out to a discussion of QFT yet. So, in addition to recommending the SEP article above, I’ll compensate by linking to this blog post at Sigpfe, which puzzles about the meaning of “particles” primarily in the context of the Unruh effect (HT: Reality Conditions). I agree that the notion of a particle makes no sense in anything like the classical meaning although there are indeed “particle” detection events.