Several types of catalysts are commonly used in carbon-carbon coupling reactions: - Palladium-based Catalysts: Widely used in reactions like the [Suzuki coupling]() and [Heck reaction](). - Nickel-based Catalysts: Often used in [Negishi coupling]() and [Kumada coupling](). - Copper-based Catalysts: Employed in [Ullmann coupling]() and [Sonogashira coupling]().