  The sensitivity of direct searches for heavy neutral leptons (HNLs) in
accelerator-based experiments depends strongly on the particles properties.
Commonly used benchmark scenarios are important to ensure comparability and
consistency between experimental searches, re-interpretations, and sensitivity
studies at different facilities. In models where the HNLs are primarily
produced and decay through the weak interaction, benchmarks are in particular
defined by fixing relative strengths of their mixing with SM neutrinos of
different flavours, and the interpretation of experimental data is known to
strongly depend on those ratios. The commonly used benchmarks in which a single
HNL flavour exclusively interacts with one Standard Model generation do not
reflect what is found in realistic neutrino mass models. As a part of the
activities within CERN's Physics Beyond Colliders initiative we identify two
additional benchmarks, which we primarily select based on the requirement to
provide a better approximation for the phenomenology of realistic neutrino mass
models in view of present and future neutrino oscillation data.
