@Alma **************
I don't know about central Asia or the middle east, but in southeast Asia, three countries receive tourists without requiring proof of onward travel:
- Vietnam requires it for their 15 day exemption, but if you go longer, you need a visa, and for that it is not required. Even for 30 days you do not need it. Also, the 15 days exemption isn't for all nationalities. Dutch and Belgians for instance have to get a visa, and hence they do not need exit tickets from Vietnam even going there for a few days.
- Cambodia requires it based on nationality. I do not know about yours, but the ones they require it from are typically non-western.
- Laos as I said requires it in no circumstance, the only country I know of doing that.
I'm not sure about that new 15 days exemption for China. I find it hard to believe that they require you to justify every minute in the country of you get a (longer) regular tourist visa, but if you go just a couple days, you are not even required to have exit travel booked. It is what the sources say though. I wouldn't dare going without, but strictly speaking, that is the conclusion.