I have to make corbels all the time, except they are usually huge and structural to a frame...Often they are carved from single blocks of wood.
I am taking from your OP you are exploring methods to fabricate these yourself? The methods offered thus far is a common one in most shops that are just mostly power tool based...and for smaller Brackets forms of Corbels like these the Band Saw method will make relatively fast work of roughing in the shape you wish to have...If you have access to a bandsaw.
If you don't have access to these large shop tools there are efficient alternatives...and still in common use...Profile Kerfing
1. You can use a Chainsaw. Please note: these are very dangerous tools if one is not accustomed to operating them. Please get qualified assistance in there safe and proper use or instruction!!
2. Much safer method (but not as fast of course) is to simply use a hand saw...This is still the most common method.
Both 1. and 2. are..."Kerfing Methods." With this method you take the stock of wood you are planning on making the bracket from and overlaying a template on its side that has the desired profile of shape you wish to have or replicate.
Once the profile from the template has been transcribed (drawn) onto the wood stock, It is a simple task of sawing to this line in 10mm to 20mm increments (this is the kerfing.)
I would share, as a wood carver from a family of carvers, that historically such work has always been done with hand tools for the most part. Even today (global perspective) it still is. So don't be discouraged if all you have is hand tools. The work will be slower (and safer) but the satisfaction much higher. In place of a Chainsaw, I suggest a Bow Saw or any sharp..."Pull Saw" that you can find that fits your grip well. Pull saws, in such work as this Profile Kerfing
, function much better than push saws.
The below photos from my Bookmarks are the fastest I could scrounge up that might help illustrate what I described above...Good Luck.