  In recent years, exciting (indirect) hints for physics beyond the Standard
Model (SM) have been accumulated. In particular, semi-leptonic $B$ decays show
deviations from the SM predictions, which, due to the ratios $R(K^{(*)})$ and
$R(D^{(*)})$ are obviously related to lepton flavour universality violation
(LFUV). However, {we point out} there are more anomalies which admit an
interpretation in terms of LFUV: The anomalous magnetic moment of the muon, the
Cabibbo angle anomaly, the CMS measurements of non-resonant di-electrons, the
difference of the forward-backward asymmetry in $B\to D^*\ell\nu$ and leptonic
tau decays. In this letter we discuss the experimental and theoretical status
of these anomalies, {compare their strength and weaknesses} and examine {and
synthesize} how they can be explained in terms of possible extensions of the SM
by new particles and interactions. Even though not all anomalies might be
confirmed in the future, this unified view of the anomalies in terms of LFUV
significantly strengthens their relevance, which is crucial in order to
construct a convincing physics case for future colliders.
