There used to be a time when there was a reliable HKG-BKK F (744 first flight of the day, then continued to SIN, then back to HKG), but that's long gone.

Also a few reliable services (in addition to the above) to/from SIN. Also long gone. Now it's just sporadic. Interesting when SQ is running an A380 on the route. A CX bean counter has determined that it's not financially viable, obviously.