I’m no expert on this question. I think quite uncommon. However, any city of interest probably has touristy areas. English speakers in countries which generally speak another language are probably familiar with places and services that cater to them. There are likely hotels, real estate companies, universities and other businesses that advertise to foreigners whom they can in some cases probably charge higher fees than locals. They may or may not be concentrated geographically.
This is the real answer, and I see that other posters have expanded on this.
Switzerland actually rates higher in both categories. Most countries that rate higher than the U.S. for livability are significantly smaller than the U.S.
And that’s the other thing.
Just because someone else is American, doesn’t mean I want to spend any time with them. The U.S. is considerably bigger, both by population and by geography, than many other countries. Which means it is also more diverse. As English is the language of trade and tourism, I am more likely to find people from other countries wanting to speak my native language, which is convenient for me.
I am aware that there is a foreign neighborhood in Shanghai, but it’s not just Americans.
In general, there may be a bit of an English bubble near English-speaking schools, but the people living there are probably short-termers. In Switzerland people can stay here on a foreign contracts for just 5 years. After that they have to get a local contract, or go somewhere else.
Which means that some of the Americans who permanently leave the U.S. get rid of that pesky citizenship. I know 2 personally, and know there are others.
Mostly in the Jerusalem area, I believe.
Israelis, BTW, tend to lump all English-speaking immigrants together, much like Americans do with Hispanics. As far of most are concerned, we’re all “Anglosaxim”.
Let’s take your example, Israel, as we moved here as a family 15 years ago.
Americans (and I assume most ex-pats) don’t forget their native languages, no matter how long they live in a different country. While they may become fluent in the local language(s), most continue to speak their native language at home, with their kids, etc. Truthfully, I doubt you’d even consider moving into a Yiddish speaking neighborhood anyway, unless you became Hareidi.
You would want to live in an Anglo area, at least for the first few years, until you improve your skills in the local language. When you first arrive, you will need help dealing with the local bureaucracy, getting a bank account set up, health insurance, phone/cell/internet/cable. You don’t really want to do all that without someone who speaks your language to give you a hand. There’s no guarantee that the person coming to fix your air conditioner or fridge will speak English. Some doctors speak English, some don’t, and some do but won’t. (I took one of my kids with me to the eye doctor a few months ago, and she was a great help translating.) You will want neighbors who can explain how things work, and can give you a shoulder to cry on when times get tough.
My kids are totally fluent in Hebrew, and my wife and I still rely on them from time to time to make calls for us so that whatever needs to be done will get done faster.
Sort of a mini (or even micro) enclave. 
Most ex-pats may not totally forget their native language, but there are some words that don’t get used as much. Both hubby and I find that the German word is easier to remember (such as Autobahn), as we use it more often. I have a friend, who is single, who can easily spend days without speaking her native language.
As my husband and I are both Americans our home language is American English. Most of the Americans (or former Americans) who I have met here are married to locals, so the home langauge is a mix of American English and Swiss German and German.
I decided to improve my German as I do not like being dependent on others, especially for doctor visits. Fortunately English is very common among the medical community, but many of the doctors do not speak it well, even if they can understand it. I did see a specialist last year who studied at Havard, which did make it easier to discuss the details of my medical issue.