Nothing's going to happen if all you do is plug them in; just scan them with an Antivirus program.
Disable "Autoplay" for all devices.
(Control Panel > Hardware & Sound >Autoplay)....
Once that is done ..
Connecting and Formatting the drives would be best , but if you are going to retrieve files from them ..
A recommendation of mine would be to do a malwarebytes scan first .
Also scanning with your installed malware/Virus scanner would not hurt. ...
Download > Install > Update > Scan the drive(s).
https://www.malwarebytes.org/antimalware...
If there is nothing of any real importance on them I would just format them completely. If not you're going to have to plug it in and scan it but that's not going to tell you if a program is pirated.
