Consider the following (contrived) example.
Draw a big rectangle and extrude. Then cut that rectangle in to 100+ separate strips by Extrude-Cut strips all the way through and all the way across. So now you have 100+ separate rectangular strips.
In my work I often have such separate but equally-thick parts all in the same model. I often need to select all the top faces and perform some function on them. Right now I do it manually.
I should mention that I have "dumb" geometry (an imported X_T or STL).
I found "Power Select" but it seems not capable of this