New pc / Download again

No,you can put them in a box and the unpack the box once you need them again. Just like laundry.

In the Steam client go to Steam > Backup and Restore Games... and go from there.

You still need to manually back up your saves, though.

I did fast search for you, here is the result. Clearly possible :)

You could backup your games and transfer the files to a USB key or the like.

Traqnsfer the data from the old pc to the new PC Via USB ?

Tho it may take just as long as re downloading the games :)

Just take out the harddrive and put it in your new PC?
If u still need the harddrive or ssd for something else just copy paste them

thank you guys