Estimated masses, in units of solar masses, for a number of neutron stars that are *not* in double neutron star binaries. Data available from https://stellarcollapse.org/nsmasses. 1.96 1.71 1.21 1.57 1.53 1.96 2.39 1.74 2.0 2.12 1.02 1.57 1.073 1.44 1.91 1.57 2.56 1.41 1.38 1.31 1.30 1.72 1.27 1.79 1.48 1.49 2.74 1.47 1.928 2.01 1.20 1.393 1.47 1.83 1.26 1.53 1.44 1.91 1.55 1.24 2.08 1.26 1.34 1.41 1.4378 1.832 1.18 1.58 1.71 1.667