Midtrinary Pride Flag
Midtrinary or midternary: non-trinary identities that are not strictly atrinary/exotrinary (aternary/exoternary); an umbrella term for midbinary, midtertiary genders, and other labels referencing gender trinary/aptoternary/aptotrinary.
Examples: demitrinary (but not necessarily demiatrinary as the other part can be anontrinary/anonternary)/viatrinary/ideotrinary [demiternary/viaternary/ideoternary], multigender experiences involving at least one trinary gender (multrinary/multitrinary), trinaryflux, etc.
This term was not defined yet, but used in an illustrative infographic from gender juxtaposition diagrams.
It should be noted that trinaries could depend on one's cultural arities, as the tertiary trinary gender could be a culturally specific identity ("third gender") or could just be neutral (neutrois/agender). Sometimes trinary/nontrinary doesn't apply to the individual either, for example when one's gender is from a quinary or senary system.