I unplugged a 1TB SSD without ejecting it first, and when I connected it again sometime later, I couldn't even see it in Finder.
I opened Disk Utility and run first aid on it and got an error (com.apple.DiskManagement.disenter error -119930878.) but after I closed it, it continued running and some minutes later, the drive was fixed and I was able to see it in Finder and use it again.
I'll remember to eject the drive properly next time before unplugging it.