File Juicer
File Juicer for macOS
Overview of Formats

Search & Extract

Images

jpg jpeg 2000 gif png pdf wmf emf tiff eps pict bmp

Video

mov mpeg avi wmv

Sound

mp3 wav System 7 au aiff

Text

ascii rtf html

From:

avi cab cache chm dmg doc emlx exe ithmb m4p mht mp3 pdf pps ppt raw swf wps xls zip and other formats

.bkf - Microsoft Backup

I have not investigated any Microsoft Backup files. File Juicer may recover some files.