I have to confess, I don't have much experience with worms, only 1 fluke I found in my own stool [most known flukes are no bigger than your thumbnail ie F. Buski
I will agree that there are probably several types of human parasitic worms we haven't characterized or made visual records of.
But to be clear, I have experience with examining poo under the microscope. I can tell you that worm eggs are big enough to recognize [under medium power] and most will float.
Worms also have a very tough "cuticle" which should be recognizable with a good eye.
Ascaris eggs are microscopic. Shroom