The names of the various patterns is somewhat flexible, every manufacturer has his own interpretation of what a clip or spey blade looks like. Some makers' small pen and spey blades look a lot alike, and so on.
And, unless you can point to a catalog listing or something, one buyer may call certain pattern something different than I would. I like JA Henckels knives, and always troll the auction sites for them. There's a seller who is constantly listing a Trapper as a Copperhead. Both are jack knives, meaning both blades are hinged at the same end of the handle. The handle shape of a Trapper is similar to a Copperhead (usually a Copperhead is a little beefier and shorter than a Trapper). A Trapper has a distinctive combination of blades, a long clip (often called a Turkish clip) and a long spey. The Copperhead usually has a regular clip blade with a drop point blade. The overall effect is Copperhead equals beefy, the Trapper equals slim. I've contacted the seller, and gotten nowhere... the usual eBay genius versus the anonymous internet know-it-all...
...and so it goes.
The drawing above is just an overview. In fact, one of my favorite patterns, the Congress, doesn't chow up there.
Way back in the early 14th century when I was learning this stuff, I memorized Levine's Guide to Knives and Their Values. The fifth edition of that book is deeply flawed, I don't remember what happened, I think Levine lost editorial control over it. But if you can find a beat-up copy of any of the earlier editions you'll find a wealth of information. Those books conain a lot of information that you'll never find on the internet.