Distribution of groups and clusters in formation redshift and mass accretion rate (z_form,Γ_200m) space for relaxed and unrelaxed populations separately. We highlight three main subsamples: 620 early-formed low-accreting and relaxed groups and clusters in red, 360 early-formed low-accreting and unrelaxed in yellow, and 482 late-formed fast-accreting and unrelaxed groups and clusters in blue. In gray we show the overall point distribution of the full sample.