In which foreign countries is it easiest to get by speaking only English, in descending order of wide knowledge of English?

if you are only including countries that do not use English as the native language, then the European countries will have the most widespread use of Englishcas a foreign language. The further north you go, the easier it is to get around in English. So, the Nordic countries are easiest. Followed by Central Europe. The same trend occurs in the Americas, where English use declines the further south you go. Africa has the opposite trend, where English is strongest in the south and declines as you you north. East asia has more English in the east and declines as you go west. South Asia has a fair amount of English throughout.

So, you want us to list on correct order most of the countries of the world?! Including those whose major language is English?

It would also depend on which part of those countries you visit. Tourist areas, and areas with much international commerce would have many people with at least basic understanding of English.

I would say the Netherlands and then, Germany, then France and Spain...