What are wrenches called that are just cut out of steel flats?

I agree with cheap that was my first thought.

They are usually open end wrenches ? with the open end In some cases they are combination one end open one end closed with 6+ sides

In the case of a skill saw those are a bit thicker but still cheap I have the proper sized combination wrench attached to my power saws in my shop with a magnet. Yes even if they were all 3/4 I would have a wrench on each one just easier having a heavy tool for me even routers I pack wrenches in their boxes.

These are often used in bicycle maintenance, because two nuts are often used to lock the bike axles.

The tool is called a cone wrench, and good ones are not cheap.

For example, this is a $75 set. Cheap sets are $20 and will round out upon application of torque

While I agree that when applied to bicycle maintenance these are called "cone wrenches", in general they're simply "thin open-end wrenches" or "tight-clearance wrenches".

If it is the method of manufacture that you want to specify, then it is 'stamped' tools, as opposed to 'forged' or 'drop forged', or 'cast' or 'die cast'.

Generally stamped tools are cheaper. They have sharper edges which are less comfortable to use, and the jaws of the spanner are more prone to straightening out or rounding.

Stamped tools are cut like a cookie from a flat sheet of metal. Cast tools have molten metal poured into a mould of the correct shape. Forging means getting a piece of solid metal and hammering / pressing it into a mould of the final shape.

Disposable Wrenches

https://www.google.com/search?q=disposable+wrench&tbm=isch

They often come included with flat-pack furniture and cheap tools. They're admittedly hard to find because they're meant to be used once and discarded. Buy a small desk from Ikea and you should get one, or just pop into the service desk there and let em know you're missing one and they will help you out.

They're common at hoarder estate sales as well.