I'm not an expert, but I believe that for the time period and locale that you're considering (i.e. "old west") there's basically two choices for chips - fancy carved ivory and rather plain dyed bone. I say that based on what I've seen in auctions from places like Potter and Potter, who occasionally have auctions focusing on antique gambling paraphernalia, and based on what I've seen turn up on
eBay. Most poker chips that are earlier than around 1900 seem to be ivory or bone. "Clay composition" came on the scene in the late 1800s and was common throughout the early 1900s, until the synthetic plastic revolution. For pre-1900s there's also mother-of-pearl tokens, but those most commonly seem to be "gambling counters" of various odd shapes rather than the round chips we're familiar with.
This site has a huge collection of pictures of antique ivory chips; you can browse around to get an idea of what "old west" poker chips probably looked like.
Bone chips, on the other hand, don't seem to be much to look at. There's not a lot of examples to be found via google, and the examples that do turn up are usually quite plain - just colored circles. Here's a few examples:
Getting a playable set of actual ivory chips is going to be somewhere between ruinously expensive and literally impossible.
I
have seen a modern set of poker chips that were specifically designed to resemble antique ivories, but darned if I can remember where I saw them. I tried to find them again but had no luck; if I do run across them I'll let you know, but please don't hold your breath.
@ekricket had a great suggestion - there are some vintage chips from the early 1900s that have a somewhat similar style to the earlier ivories. Chips like these were made by the US Playing Card Company, you can see representative samples
here. They turn up on
eBay from time to time. They're not particularly valuable, but they're hard to find in playable quantities.
I think your best option is to engage a graphic designer (there are several here on PCF that do excellent work) and have them come up with a design that invokes the old west feel of vintage engraved ivory chips, and then have them custom-printed on ceramics by
@ABC Gifts and Awards . You'll end up with a beautiful and unique set of chips with a great feel to them.
Just my two cents.
Welcome to the forum!