Searches for Fourth Generation, Vector-like Quarks and ttbar Resonances with the ATLAS Detector

The LHC operation at the high center of mass energies has opened the insight into the potential production of exotic heavy particles. A summary of the searches for the heavy quarks and the heavy bosons decaying into the top-antitop pairs ($t\bar{t}$ resonances) with $14.3~\rm{fb^{-1}}$ of the ATLAS detector data at $\sqrt{s} =8~\rm{TeV}$ is presented here. The searches for heavy quarks are performed in frameworks of the chiral fourth generation and vector-like quarks. One of the searches is also sensitive to the production of four top quarks and positively-charged top quark pairs. The searches for the $t\bar{t}$ resonances rely on the narrow width topcolor leptophobic $Z'$ and broad width Kaluza-Klein gluon as bench mark.