These edge tools are made by Auriou Toolworks, Robert Sorby, Ray Iles, Gransfors Bruks, Pfeil and Flexcut.
Each is different and you must chose which best suits your purpose. If you need to strip bark from a large log then the Gransfors Bruks drawknife is the perfect beast for that particular job. The Auriou drawknives are made using old blacksmithing techniques and follow patterns of old designs.
An inshave is a bent drawknife, so you can hollow out and a scorp is a fully circular blade with a single handle.
There are dozens of designs for drawknives and they are suited to particular crafts, e,g cooper, chairmaker, loghome builder, longbow maker etc. Salaman's Dictionary of Tools describes them all with line drawing illustrations. This great bible for hand tools should be in any hand tool enthusiasts library.