Massive form factors are important building blocks
in higher-order corrections to various observables like
heavy-quark production, top quark decays or muon-electron
scattering, where they describe the virtual contributions.
Furthermore, they show universal infrared behaviour which makes
them interesting to study also in the context of the infrared
structure of QCD amplitudes.

In these proceedings we present our recent calculation of singlet
and anomaly contributions to the massive quark form factors,
which is based on expansions around singular and regular points
of the master integrals and numerical matching.
This calculation completes the calculation of
the massive form factors for external vector, axial-vector,
scalar and pseudoscalar currents up to $\mathcal{O}(\alpha_s^3)$.