The last decade has seen the flourishing of this new genre well beyond the three most familiar disciplines: philosophy of mathematics, philosophy of physics, and philosophy of biology. (I suppose philosophy of mind is a close cousin, even if it is not quite the same as what one might call philosophy of cognitive science.) A selection of recent titles:
Baird, Scerri, and McIntyre, Philosophy of Chemistry (2011)
Bechtel, “Philosophy of Cell Biology” (2019)
Boniolo and Nathan, Philosophy of Molecular Medicine (2016)
Brigandt, “Philosophy of Molecular Biology” (2018)
Broadbent, Philosophy of Epidemiology (2013)
Cartwright and Montuschi, Philosophy of Social Science (2014)
Fagan, Philosophy of Stem Cell Biology (2013)
Gabbay, Thagard, and Woods, Philosophy of Statistics (2011)
Green, “Philosophy of Systems and Synthetic Biology” (2017)
Griffiths and Stotz, Genetics and Philosophy (2013)
Kincaid and Ross, The Oxford Handbook of Philosophy of Economics (2009)
O’Malley, Philosophy of Microbiology (2014)
Plutynski, Explaining Cancer (2018)
Thagard, Woody, and Hendry, Philosophy of Chemistry (2012)
Valles, Philosophy of Population Health (2018)
Beyond these there have also been several new books in the philosophy of medicine: Broadbent, Howick (on evidence-based medicine), Stegenga, Thompson and Upshur.
A rather glaring omission is the philosophy of engineering.