GDM Geos Diskmonitor v2 by H. Luyten (1987) - Found this interesting track/sector editor that apparently came with a German book called "C64: Everything About Geos".  Besides the neat sprite hunting feature, it also has a special value to GEOS users as quoted from Heiko Herrmann, it "is aware of the special file structure format of the VLIR files, so the "F5 Directory" mode will be able to jump you to the actual pages of the VLIR files."  

Here is a thread over at Facebook if you want to add any further details you may know about the program.