Is there a single word or a phrase that means the most popular one of some set of service tiers/offerings? For example a service provider asks "Do you want Deluxe, Premium or Gold?" then instead of asking them back which one is the most popular, one can simply respond with something like "Give me X" and that would imply the most popular one.
There are a few options, depending on exactly what kind of popularity you're referring to. If you want what is popular recently, you could say "Give me whatever is trendy.
currently popular or fashionable
If you want what is most popular of all time, you have a few options, one of which is to do what you said and ask for what is most popular.
You could also say "Give me whatever is standard."
a : regularly and widely used, available, or supplied
b : well-established and very familiar