Almost all the leather I use is a byproduct of the meat industry. When a cow is killed for its meat any part of it that can be used (which turns out to be a surprising percentage) is used, including the skin. Leather is a very versatile material and usually the only difference between one kind of leather and another is just in how it's tanned.
Vegetable Tanning refers to treating the leather with extracts (tannins) from plants, generally oak or hemlock, to tan it. As a leather, veg-tan has numerous properties but most notably it can be molded and carved. I'll often refer to veg tan as "tooling leather".
After being tanned, oiled leathers are treated with various oils and waxes that seal and protect the leather. This makes a material that's both durable and pliable and can be used to make a wide variety of things. When most people think of leather they're usually imagining some variety of oiled leather.
As the name implies this is a cowhide that has been tanned in the same manner as a deerskin. The result isn't quite as supple as deerskin tends to be, but it's pretty close and a bit more durable. Available in a wider variety of colors than most non-suede leathers, DC is inexpensive enough to be used as a lining and durable enough to be an outer shell or skin.
Popularized in stories of the Wild West and cowboys, latigo is a cowhide that has been heavily treated with waxes and certain oils. The result is a heavy duty leather that's as close to impervious to the elements as leather can get. Frequently used for horse tack, field gear, or for anything that needs to be hard wearing. Traditionally only available in burgundy (pictured) or black.
Suede (aka split leather)
Not that long after WWII it became commonplace to use a machine to split a hide length-wise into narrower hides. This allowed one hide to be turned into half a dozen thinner hides and dramatically reduced the price of leather. The top layer would retain the grain and would be tanned normally. The rest of the hides became suede. Suede is fairly soft and flexible, comes in a variety of colors, and is frequently used for clothing, lining, or pouches.
Milling refers to a tanning process that involves rolling a tanned hide in a heated drum for a long period. This loosens the collagen fibers in the leather resulting in a pebbly texture and a very flexible leather. Milled leather is most often used for wearable items or accessories.
When tanned in the traditional manner, deerskin becomes a very flexible, elastic material. It's famous for its ability to form itself around complicated shapes (like hands) that makes it perfect for applications other leathers wouldn't be well suited to. Traditionally only available in black, brown, tan, or sometimes white.
Pigskin has a distinctive spotted pattern that usually makes it pretty easy to spot. It's usually tanned with a glaze to give it a smooth, glossy surface and is frequently used as a lining.
A common material mostly made of recycled cardboard or sawdust mixed with a binding agent or glue. On its own it's not very pretty but it's inexpensive, rigid, and relatively easy to work with. I almost exclusively use it to build rigid structures (like toolboxes) that will be wrapped in leather or some other material.
A plastic made from cast off plant parts (mostly corn husks) that happens to be recyclable and biodegradable. Because it's more environmentally sustainable than the other plastic used in 3D printers I tend to use it exclusively. My particular printer isn't very good at detail work but it's well suited for printing hardware or pieces I can finish manually. My selection of colors for filament changes pretty often so if you have a particular color in mind please contact me to learn if it's available.