I recently had to return my faulty M.2 SSD which was my boot drive and I'm just wondering if it's possible to keep the applications which are installed on the other drives for when I reinstall windows on the new drive, pretty much just my games on my 3rd drive but I'd prefer not to have to reinstall everything if it's not necessary. Of course I will do so if I do have to but it's only the games I'm worried about really.
depends on the games and any distributor or client being used with them.
you would have to try each one to see if they can still run on the new install.
some games need specific registry entries,
some need system drivers in place, etc.
as long as they are using the same drive letter and install path;
launching Steam, Origin, Epic, Gog Galaxy, etc should be able to recognize the game files in place and just download any system files necessary.
your OS drive will also store a lot of the user information required for most games.
if you don't have backups of your Users & ProgramData folders you may have lost most of your save states and configuration files that aren't stored on the cloud.