The physics reach and feasibility of the Future Circular Colliders (FCC) are currently being investigated in the form of Conceptual Design Reports. The ultimate goal of FCC is to collide protons with a centre-of-mass energies of 100 TeV, thus extending the reach of the current HEP facilities. This high-energy regime opens new opportunities for the discovery of physics beyond the Standard Model (SM), but also for precise measurement of fundamental parameters of the SM. Following the LEP/LHC model, it is obvious that the first collider that should be operated, is an electron-positron machine, FCC-ee. It aims at collecting multi-ab$^{-1}$ integrated luminosities in $e^+e^-$ collisions at different center--of--mass energies, yielding $10^{12}$ Z bosons, $10^8$ W$^{+}$W$^{-}$ pairs, $10^6$ Higgs bosons and $10^6$ $t\bar{t}$ pairs. In these proceedings we explore the physics reach of the proton-proton Future Circular Collider (FCC-hh) for searches of new particles decaying to two high energetic leptons $l^{+}l^{-}$ ($l=e, \mu, \tau)$, jets (non-tops), tops and W/Z boson. We discuss the expected exclusion limits and discovery potential for benchmark models predicting new massive particles that result in resonant structures in the invariant mass spectrum. The study is based on large statistic samples of generated events processed through a parametric simulation of the expected performance of an FCC-hh detector. The center--of--mass energy of $\sqrt{s} =100$ TeV makes it the ultimate machine for such new heavy particles, and studying their characteristics is also extremely relevant to discuss the main limitations of the detector to precisely discriminate high energetic top-quarks or W/Z bosons from standard QCD-jets.