Just installed a new SSD and am wondering about migrating my large game folders to it. Can I do that at all? What issues will I need to deal with if I do so?

It depends on the game. If your new drive appears at the same folder as the old one, then you should be fine. This might happen if your games are on a secondary drive, you copy them to a new drive, then take the old drive out of service and put the new drive in its place. You might also be planning to keep all your old drives in use. If the drive letter or path of the game will be changed, then you may have a problem. Some games store path-related information in the Windows registry, so moving them to a different folder will cause a problem. Other games assume everything is in the folder where the executable is stored, so as long as you keep all the pieces together, it will work.

The most likely problem you will encounter is the game claiming it cannot find its data files, because it is looking for them at the original path. This can almost always be fixed with a reinstall, but be careful that the installer doesn't helpfully delete your saved games in the process.

Which games do you want to move?

Do you mean that you want to move the downloaded GOG installers to a new drive? Those are necessarily portable since we all get the same installer, so you can put those wherever you want without issue.

https://www.gog.com/forum/general/move_installation_folder

Perfect! Thanks!