When I was surfing keh I found "Non-Mfg Zoom Lenses" and "Non-Mfg Fixed Focal Length Lenses"? What is the meaning of "Non-Mfg"?
It's short for "non-manufacturer". Of course, all lenses have a manufacturer — you can't grow them on trees! — but the expression means that the lens manufacturer is different from the company that makes the cameras the lens is designed for.
This is also known as "third party" (the "first party" being the company and the "second party" being you — or maybe the other way around; in any case "third" is definitely some other company).
If you're looking for lenses for Pentax K mount, for example, lenses made by Tamron, Tokina, or Sigma would be in the "non-mfg" category.