The following figure collects measured NS masses. It is available as a downloadable pdf file, too.
It has been prepared by L. Suleiman and M. Fortin and is regularly updated from
Currently it contains mass measurements for 75 NS within 68.3% confidence level except for sources presented with a diamond symbol and GW170817. The symbol * refers to mass measurements for which it is unclear if the source is a Neutron Star or a White Dwarf. The following classification is adopted: binaries with two neutron stars (DNS), millisecond pulsars (MSP) with spin frequency f > 50 Hz and with a companion that is not a NS, slowly rotating pulsars (SLOW) with spin frequency f < 50 Hz not in a DNS, X/OPT for NSs measured through X-ray or optical observations (as opposed to radio in previous categories) and GW for NS mass measurements using detection of gravitational waves.
The corresponding data can be found in the following files DNS.dat , MSP.dat , SLOW.dat , XOPT.dat and GW.dat , respectively.