Recent advances in jet tagging allow for high-energy colliders such as the LHC and prospective FCC to place phenomenologically relevant bounds on rare top, Z and Higgs decays involving flavored jets. In particular, I will present a novel strategy for measuring branching fractions of top quark decays, targeting specifically t→jW, where j is a light quark jet. Including additional complementary observables into existing analyses paves the way to access directly the standard model value of |Vtd|^2+|Vts|^2 at the HL-LHC. A similar strategy can be exploited at the FCC-ee to probe flavor violating Z and Higgs boson decays to quarks. In particular, I will discuss the prospects for reaching the SM value of Br(Z→bs), as well as for surpassing indirect neutral meson mixing constraints on quark flavour changing Higgs boson couplings.
