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.