Fastest way to check for bad sectors in HDD?

I have a bunch of disks, probably 50 or more laying there, I know some of them are broken and some should still work fine, I need a way to check them without wasting days.

Do you know any tools besides badblocks, that can do it without taking too much time?

You have to check some SMART utilities.

You can use "Disk Utility" (aka palimpsest or gnome-disks depending on the Ubuntu release) for this.

In command line I suggest you install the smartmontools package (sudo apt install smartmontools) and play around with smartctl.

Example:

sudo smartctl --all /dev/sda

If your drives have SMART, I would go about this by installing "gsmartcontrol" and doing a short test on all drives. Then throw away the ones that do not even pass the short test or display errors/warnings and perform a long test on the remaining drives.

To truly find out if a drive is damaged or not, I guess you will need to check every sector of it and that's what the long test does.

But I am no expert, maybe there is a better way?