Actually, about Japanese content and streaming, you can't find much at all on YouTube, Dailymotion, etc because Japan has some of the most strict copyright laws in the world. Have you ever tried to find an Arashi MV on Youtube?! They practically do not exist. Occasionally, you may get lucky and find a fan has uploaded something, but they will get removed promptly. Same with dramas. It is extremely hard to find streaming Japanese content of any kind.
As for the other countries and sites, there used to be a site that streamed Mainland Chineese and Taiwanese dramas. A lot were raw but some were subbed. I think it was Sugoideas.com.
Viki has a lot of Mainland Chinese dramas now. They also have some Taiwanese dramas. I have noticed, though, that with the rise in popularity of Mainland dramas these last couple of years, Taiwanese dramas are harder to find.
Kissasian still has the best collection of dramas that I can't find on Viki or Dramafever.
With Thai dramas, it is also hard to find content but I have found them on Youtube and Dailymotion.
I don't have much experience with Hong Kong dramas, but I have seen some on YouTube.
Finally, once in a blue moon, a random drama app will pop up in the Google Playstore. The ones I have found and tried over the years pretty much just access streaming sites like gooddrama or kissasian. They are usually removed pretty fast and the developers eventually lose interest in updating them, so they stop working.