Nickel-Catalyzed Reductive Couplings of Aldehydes and Alkynes -- Reductive C–C Bond Formation after Epoxide Opening via Electron Transfer -- Catalytic Reductive Coupling of Carbonyl Compounds – The Pinacol Coupling Reaction and Beyond -- Catalytic Reductive Coupling of Alkenes and Alkynes to Carbonyl Compounds and Imines Mediated by Hydrogen -- Reductive Aldol, Michael, and Mannich Reactions -- Recent Advances in Alkene Hydroformylation -- Nickel-Catalyzed Reductive Coupling of Dienes and Carbonyl Compounds -- Reductive Coupling of Unactivated Alkenes and Alkynes.