Grid for copying photos from laptop
We don't really allow for product recommendations, but you can make your own grid overlays:

Buy a sheet of flexible plastic, and use a permanent marker and ruler to create a grid with your preferred scale, and simply put it up against your monitor.
Usually it can rest against the borders of the screen, but a little tape will definitely hold it in place.

In an image editor like Photoshop or the free open-source Gimp you can:

add guidelines;
(add a transparent layer and) add lines on top of the reference image (and save that layer to use it whenever you need it);
make use of the feature to show grids (the size can be adjusted);
find premade grids on transparent background images online.