Gordon Bennett is an expression that is commonly used to show disbelief or amazement. However, there are many synonyms that can be used in place of Gordon Bennett to convey the same sentiment. Some alternatives include expressions like "Good grief!", "Oh my goodness!", "Wow!", "Unbelievable!", and "Holy cow!". Other more colorful phrases like "Bloody Hell!", "Blimey!", or "Crikey!" can also be used. No matter the phrase chosen, all these alternatives share the same ability to show surprise, shock, or disbelief in a more varied and colorful way.