Creating a Quad of specific size (without scaling)

This might be a really stupid question, but I wasn’t able to figure this out for a long time…
When you create a Quad in the scene, it is created with a default size (with its edges of 1x1 Unity units). But what should I do to create a Quad of a specific size (in Unity units), say of a rectangular shape rather than a squared one? Scale tool is not the solution for me since it ruins a lot of what I would like to achieve (I’d like to manipulate scaling for some other tasks, for example).

Do I have to use a 3D-modeling tool just to do that? If it’s not built in into Unity, maybe there are assets for such functionality?

You could create a mesh from script, or use Blender to model it, or just scale the quad and do your scale manipulation on a parent transform.