What is this kind of 3D text effect called? It's made with either overprinted letters, or different colored layers into a fake 3D effect.
The 'effect' is simply called a 'bevel'.
You can emulate it to an extent using any number of bevel filters in a variety of illustration and design software products, but in this particular example, it was drawn this way. Either in a program such as Adobe Illustrator, or by using an existing typeface already drawn this way. An example of such a face is Detroit.
As a typeface, the effect is achieved by layering different variants of the same typeface--each variant a separate color you can create.