This review provides an overview of recent advancements in the field of nonlinear Hall effects (NLH), focusing on theoretical foundations and experimental progress. It highlights the quantum origin of the second-order Hall response, particularly the Berry curvature dipole (BCD), which can arise in systems with broken inversion symmetry. The impact of disorder scattering on the nonlinear response is also discussed. The review explores the possibility of obtaining nonlinear Hall responses beyond the second order and examines symmetry-based indicators essential for the manifestation of NLH effects in time-reversal symmetric crystals. It presents theoretical models and candidate materials that exhibit significant and tunable BCD. Experimental reports on measuring both intrinsic and extrinsic nonlinear Hall effects across diverse material classes are summarized. Additionally, the review discusses other intriguing nonlinear effects, such as nonlinear planar Hall, nonlinear anomalous Hall, and nonlinear spin and valley Hall effects. Finally, it outlines open questions and challenges in this rapidly evolving field.This review provides an overview of recent advancements in the field of nonlinear Hall effects (NLH), focusing on theoretical foundations and experimental progress. It highlights the quantum origin of the second-order Hall response, particularly the Berry curvature dipole (BCD), which can arise in systems with broken inversion symmetry. The impact of disorder scattering on the nonlinear response is also discussed. The review explores the possibility of obtaining nonlinear Hall responses beyond the second order and examines symmetry-based indicators essential for the manifestation of NLH effects in time-reversal symmetric crystals. It presents theoretical models and candidate materials that exhibit significant and tunable BCD. Experimental reports on measuring both intrinsic and extrinsic nonlinear Hall effects across diverse material classes are summarized. Additionally, the review discusses other intriguing nonlinear effects, such as nonlinear planar Hall, nonlinear anomalous Hall, and nonlinear spin and valley Hall effects. Finally, it outlines open questions and challenges in this rapidly evolving field.