Single non-gate SN74AHC1G04, M74VHC1G04, M74VHC1GT04, NL17SZ04, NL17SV04, NLU1G04;
SN74LVC2G04, NL27WZ04, NLU2G04;
SN74LVC3G04, NL37WZ04, NLU3G04;
The four and five non-gates have never been seen, and the six non-gates are the most common.