I use polarizers more than anything else, schnieder, tiffen, I use them all. The best polar I think is the Tru Pol. I also have grads that I never ever use (waste of money) I have a couple of tricks that I use, here they are.
Instead of buying several ND filters, I put two polarizers in the mattbox and rotate one to give me the amount of ND I want. Try it. It works beautifully. and much less expensive than buying several ND filters.
Next tip, I went to a glass shop and asked them to make me 4x4 squares out of the best and colorless glass they have, 1/8th inch thick. These are what I use for a protective shield if I am mounting the camera to a car etc. to protect from flying rocks or sand. It just protects my expensive filters and they are basically throw-aways. These have a very slight color to them, sometimes, but it is always easily corrected in the white balance.
Tiffen Pro Mist 1/8 or 1/4 max.
Polarizer.
NDs.
I have a beautiful sunset grad that is pretty every once in a while.
Once in a blue moon: Enhancing or Gold Diffusion.