Estimated masses, in units of solar masses, for a number of neutron stars that *are* in double neutron star binaries.  Data available from https://stellarcollapse.org/nsmasses.

1.559
1.174
1.291
1.322
1.3332
1.3452
1.4398
1.3886
1.358
1.354
1.3381
1.2489
1.312
1.258
1.3655
1.2064