Change "most First World countries" to "most Western countries"; Japan, Korea, Singapore and Taiwan are first world countries (at least in the sense 'first world' means economically developed).
And what happens in those countries in terms of notice period? I'm actually wondering specifically about those countries too. Otherwise, all we have left is the US + Europe, more or less, I believe.
In Singapore it's 1 day to 4 weeks, depending on how long they were employed[1]. Taiwan is 10 to 30 days, depending on length of employment[2]. Korea is 30 days[3]. Japan is also 30 days[4].
I'm Australian, and it's also one to four weeks notice here, depending on how long the employee's been employed at the company[5].