I think at this point the zero cal/low cal ones are more popular. I don't know anyone who drinks Black Monster, while White Monster (zero cal) is so popular it's literally a meme. You go to a store and most of the shelf space is the low cal/zero cal options.
So not the original is 160mg as are most of their options, only the low carb monster is 140mg meanwhile Java monster hits 300mg. https://www.caffeineinformer.com/caffeine-content/monster
Starbucks has a wide range of coffee at different sizes with different amounts of caffeine. A 16 or 20oz standard double expresso is 150mg as are many other options. https://www.caffeineinformer.com/the-complete-guide-to-starb...