I have a 1997 Toyota Camry. Water was collecting on the front PASSENGER floor after a rain. I opened my sunroof and found the front drainage holes (about 1/8" diameter) in the corners of the track sunroof track. They looked clear. I poured a bottle of water in track and watched the result. Sure enough, water started dripping from the right ride of the glove box on to the floor. I started tearing out the interior panels to trace the leak. What I found is that if I poured the bottle of water REALLY slow into the sunroof hole = no leaks. But if I pour it too fast the small 1/8" hole cannot keep up and the track overflows! THAT is where the leak comes from in my car! If water overflows the track, then it makes its way down the column trim, around the glove box and on to the floor.
So I need to help the 1/8" sunroof hole drain faster. I took some 18AWG TFFN electrical wire and jammed it into the hole to help clean it out. I then removed the black plastic mud flap behind my front tire and blew out all of the leaves and rotted debris that where behind that flap. It was packed with junk! I poured more into the 1/8" hole and it seemed to drain quicker.
I hope this information helps others.