Next thing to try since it wasn't is the bottom bracket is either too tight or too loose and while at it check the pedals and chainring bolts. While the cranks are off, spine the bottom bracket, if it's rough the bottom bracket is shot and needs replacement if smooth and no slop it's fine still. Go through that and still creaking, it's either the seatpost fixing bolt(s) or it's in the hubs. If not, you may need the frame to be inspected. Wouldn't hurt to inspect the chainring itself either. A screwed up chainring tooth could cause the noise as well, especially if there is a grinding sound.

Clicking sounds are hard to diagnose.