Electroweak-penguin decays are rare, flavour changing neutral current processes that can only take place at loop level in the Standard Model (SM). They provide ideal laboratories for the indirect search of beyond SM effects, as heavy new particles can participate virtually in the decay to cause detectable deviations from theory predictions. The measurements of the properties of these decays have revealed seemingly coherent tensions with the SM. Another group of decays used to test the SM is that of tree-level, semileptonic $b \rightarrow cl\nu$ processes. Due to their large branching fractions and manageable theoretical uncertainties, they are also sensitive probes for new physics effects. These proceedings discuss a selected number of recent measurements made by the LHCb collaboration in the aforementioned areas.