The Power Cartridge was a very nice Snapshot / Freezer cartridge. Again great for by-passing copy protection. You can backup the snap shot to disk or tape. There was also a monitor. You can learn more from the Wiki on it here.
Trackmimic was another disk back up system that you installed into your 1541 disk drive.
Used Diskmimic 5+ software.
Download the D64: Trackmimic
Track Master would display the 1541 drive head track and half track positions. This would help you to identify essential tracks, bad tracks and load sequences. You electronically bypass write protection tabs. BUT I can not find any more information about Track Master. How does it work, how does it install? etc..
Top Secret Stuff was a set of tool for your Commodore 64.There was two releases Top Secret Stuff ONE and Top Secret Stuff TWO.
I feel the first one had more interesting programs on it like the Disk Doctor, EA Copier, Track repair, 1/2 track reader and formattor.
Was there a Top secret Stuff THREE?
Diskmimic 5+
Released in 1984 claims at the time it would back up virtually all existing disk for the Commodore 64 including Copy Protected disk.
Diskmimic was also the software used by TrackMimic (A device you installed into your 1541)
Here is an NZB (NZB is an XML-based file format for retrieving posts from Usenet servers) file to download all of the Zapp! 64 magazines in PDF from Usenet.
I personally use Newsbin as my downloading program and Giganews server.
DOWNLOAD zzap64
I can post more if anyone is interested!