This paper presents a classification of dimension-six operators in the Standard Model (SM) Lagrangian, considering baryon number conservation. The authors find 59 independent operators, compared to 80 in the original work by Buchmüller and Wyler. These operators are divided into three categories: those containing 0, 2, and 4 fermion fields. When baryon number conservation is relaxed, four additional operators appear in the four-fermion sector. The classification is based on the SM gauge symmetries and the requirement that operators are not redundant, i.e., they do not vanish by the equations of motion (EOMs). The authors also note that some operators in the original work are redundant and do not contribute to on-shell matrix elements. The classification is verified by comparing with the original work and showing that the new set of operators is complete and independent. The paper also discusses the implications of these operators for phenomenology, particularly in the context of top quark physics and CP violation. The authors conclude that the new classification is more accurate and complete than the original work, and that the number of dimension-six operators is significantly smaller than previously thought. The paper also notes that the classification of four-fermion operators has been independently verified in a recent paper.This paper presents a classification of dimension-six operators in the Standard Model (SM) Lagrangian, considering baryon number conservation. The authors find 59 independent operators, compared to 80 in the original work by Buchmüller and Wyler. These operators are divided into three categories: those containing 0, 2, and 4 fermion fields. When baryon number conservation is relaxed, four additional operators appear in the four-fermion sector. The classification is based on the SM gauge symmetries and the requirement that operators are not redundant, i.e., they do not vanish by the equations of motion (EOMs). The authors also note that some operators in the original work are redundant and do not contribute to on-shell matrix elements. The classification is verified by comparing with the original work and showing that the new set of operators is complete and independent. The paper also discusses the implications of these operators for phenomenology, particularly in the context of top quark physics and CP violation. The authors conclude that the new classification is more accurate and complete than the original work, and that the number of dimension-six operators is significantly smaller than previously thought. The paper also notes that the classification of four-fermion operators has been independently verified in a recent paper.