Recently I did a friend a favour and installed Linux Mint on her laptop as she was a bit frustrated with Windows. Unfortunately I assumed she’d backed up everything before handing it over to me, so I re-partitioned the whole drive to ext4. She hadn’t.
On the bright side the computer was quite new and the only thing she wanted from the disk were some photos she’d taken. Well, that just made it my lucky day because there just happens to be a tool specifically for recovering photos (and a myriad of other filetypes) from disks that have been written over: TestDisk