This abstract, "Newtonian explanation of galaxy rotation curves based on distribution of baryonic matter" uses an argument (not DM or MOND) I've not seen before. https://arxiv.org/abs/1406.2401

(It says that 'A large number of likely galaxy mass distribution profiles should in fact produce flat or accelerating rotation curves similar to those observed in reality.')

Older (2007) abstract: Kepler's third law (works for the solar system) might not apply because of galactic mass distribution. http://www.marmet.org/cosmology/nonkeplerian/galaxy.html

Five years old; didn't get a chance to find a counter-argument, but worth mentioning.