Are there any good resources to help determine the types and grades of woods out there?

Grade is a very subjective thing. What one seller declares to be a AA or AAA blank another calls Exhibition. If you want to learn about wood, see multiple examples of every type and can travel to Vegas, you need to visit Cecil. Just like when you visit a Casino you need to limit yourself to a set amount of money. Tell him what you want and watch him pull blank after blank to dazzle your eyes.

You want to shop in person. Grain flow in the wrist, grain flow left to right over the entire blank and density of wood just don’t show well in photos. People buy flash too often and forget a stocks real purpose is function first.

I think there is a YouTube video of him explaining stock wood that you can watch. Also on this site are a couple good articles Pete Hyatt wrote about a decade ago. The information is still current.

That's the absolute truth. But if you can't visit, tell him how much money you have to spend and what sort of wood you like. Send him a picture or two of examples of what you like and then he will send you photos of several to pick from and if they won't do, he will send several more.

I am always stunned when I buy wood from that man.

I agree with KYJon concerning gun stock grading, grain flow, etc. What he said about people making the mistake of buying flash and neglecting to think about function is so true. The articles by Pete Hiatt in the "Other Useful Information" section of this site are a very good place to start too. A couple hours with Cecil, if he has that much time, would fill your brain and give sensory overload. The answer to your question is not cut-and-dried (no pun intended), because the subject is huge. As with many things, there is also a lot of misinformation to sort through.

Going from memory, I believe it was David L. Westbrook's book "Professional Stockmaking: Through The Eyes Of a Stockmaker" that had a pretty good accounting of most all commonly used gun stock woods, and descriptions of their attributes such as grain, figure, density, stability, ease of carving, ease of checkering, and overall suitability. But even if you confine your interest to Walnut alone, prepare to spend many many hours learning about the differences between species, subspecies, and cultivars, and the great number of variations found even within different trees of the same species... or even different parts of the same tree! It's a fascinating subject though, and very useful to be able to avoid spending a lot of money on wood that may not be well suited for gun stocks.

I used woods for stocks that others have rarely used like Zebrawood, Holly and even Salt treated Pine. Plus the normal things like walnuts of English, Black, Claro, Cross hybrids, grafted blanks, cherry, maple (about five different types), myrtlewood, a few exotics I don’t even recall their names, flat , quarter, fiddle, burl and crotch blanks. Everything works and they all have their drawbacks.

Here's the youtube video at Cecil Fredi's:
https://youtu.be/m9DmqPyouPE

I’ve bought wood from Cecil in Vegas and it was one of the highlights of my whole career in messing around with old guns. He’s amazing and the wood is amazing.

I recently purchase a stock blank which included a piece of complementary wood for the forend.
The process from the moment I emailed Cecil could not have been easier or gone smoother.
Explained I wanted a piece of nice figured English walnut for a custom Fox project and that I wished to spend about $800. With in a few hours I had a dozen options with clear pictures. Cecil followed up the next day asked if I had questions and sent a few more options. Selected the blank and sent the money. Blank arrived professionally packed and even nicer than I had imagined.
I would not need to look anywhere else in the future.

there is enough fine walnut trees in Kashmir to make you a millionaire, but how could you ever do business in that region? Hope someone figures it out.