This chapter reviews the new collision models that have emerged in the DSMC method over the past few years. The new collision models for the two categories, i.e., models based on the Boltzmann equation and models based on the Kac master equation, are presented. However, the main focus is on the BT family schemes (i.e., SBT, ISBT, GBT, hybrid NTC-GBT-SBT-TAS, SSBT, SGBT schemes), which are based on the Kac master equation (or Stefanov equation). For each collision models, the collision algorithm, the obtained results, a comparison with traditional DSMC, and the achieved improvements will be described. At the end of this chapter, new treatments related to the DSMC collision procedure are introduced and discussed. These techniques primarily focus on eliminating collisions or reducing the time required for the DSMC collision process in near-continuum flows. The considered approaches are DSMC-Fokker-Plank (DSMC-FP), Low Diffusion-DSMC (LD-DSMC), low-variance deviational simulation Monte Carlo (LVDSMC), and collision limiters.