Precise measurements of the properties of the top quark test the Standard Model (SM) and can be used to constrain new physics models. As it may be significantly enhanced by the presence of new physics, the $\mathrm{t\overline{t}}$ production charge asymmetry is measured inclusively and differentially using the 8~TeV dataset of the ATLAS experiment at the LHC using both the lepton+jets and dilepton channels, including a dedicated measurement for highly boosted top-quarks. The top-quark is predicted in the SM to decay almost exclusively into a W boson and a b-quark. We present a wide range of searches for non-SM top quark decays using the 13~TeV ATLAS dataset, including t$\rightarrow$qH and t$\rightarrow$qZ decays. In addition, measurements of the spin correlation and colour flow in $\mathrm{t\overline{t}}$ production are presented.