  I give a short summary on scenarios with new physics scalars that could be
investigated at future $e^+e^-$ colliders. I concentrate on cases where at
least one of the additional scalar has a mass below 125 GeV, and discuss both
models where this could be realized, as well as studies which focus on such
scenarios. This work is based on arXiv:2205.09687, and partial results were
also presented in arXiv:2211.10231.
