The Action Replay Mk.IV by Datel Electronics (1988) is the ultimate backup cartridge.  This manual covers both the standard Acion Replay Mk.IV and the
Action Replay 'Professional' Mk.IV.

BUTI is a Basic programming utility cartridge which provides seventeen programming aid commands, and an extra 3K of user memory. BUTI gives you increased control of programs and
variables, and eases programming through its Basic error catching and powerful editing features. Also with one instruction it formats the VIC to imit~te the minimum memory or +3K configurations, or +BK when used with other expansions on a multi-cartridge board.

HES MON 64 [cartridge] Instruction Manual for the Commodore 64

The following is intended for people who are unfamiliar with the uses of a machine language (M.L.) monitor program. However, it is not a tutorial in the architecture of the VIC or the 6502. Nor is it intended to teach 6502 assembly language programming. In fact, some knowledge of assembler language will be most helpful. It IS intended to help the beginner get started in using HESMON. Even those who know nothing about the 6502 or the VIC will find some of HESMON's corrmands useful (see, for

Mach 5 by Access Software was a disk speeder cartridge / disk combo for the Commodore 64 that greatly enhanced the transfer speed of the 1541 floppy drive.  It was later followed up by Mach 128 for the Commodore 128.

Here is a link to the program disk

Ms. Pac-Man [cartridge] Game Manual for the Commodore 64

Music Composer [cartridge] Instruction Manual for the Commodore 64

One Step Utility Cartridge Manual for the Commodore 64

The VIC 20 PROGRAMMER’S AID CARTRIDGEhas been designed to help both new andexperienced BASIC programmers to write, editand debug programs quickly and easily. This isachieved by the AID commands which areautomatically incorporated into the

Rootin' Tootin' [cartridge] manual for the Commodore 64

C64-LINK II is an expansion cartridge for the Commodore 64 that adds 16 disk commands and a machine language monitor to the Cornrnodore 64.  It also allows you to use the "parallel" and "IEEE" modes of data transmission, permitting the use of any parallel printer, IEEE printer or IEEE disk drive.  The C64-LINK II cart ridge takes up no memory and is completely transparent to commercial or home software.

The Utility Cartridge saves you time and energy. In just two keystrokes you can perform BASIC functions that normally take several steps to complete. A RESET BUTTON lets you reset the comptiter without turning your computer off and on. Also, with machine language monitor software you get 30 additional machine language programming commands.

Stack Super Help is a programmer's utility cartridge featuring:

• 20 Additional BASIC Commands
• Disaassembler and Monitor
• Disk Operating System Support
• 2 Pass Assembler

Here's a link to the .PRG version of the cartridge.

The SUPER EXPANDER 64 is a powerful extension of the BASIC language in your Commodore 64 computer. Previously, you had to Peek or Poke specific memory locations to access your computer's graphics and sound features. Now, the SUPER EXPANDER 64 provides new BASIC commands so you can easily access the Commodore 64's many features . Simply "plug" the SUPER EXPANDER 64 cartridge into your computer and turn on the power.

Here is a link to the ...

Your Super Expander cartridge is the most versatile cartridge you can buy for your VIC 20 Personal Computer. It adds an entirely new set of color, graphics plotting, music and function key commands to your VIC’s vocabulary... AND ... adds 3K extra memory (RAM) so you can write and RUN larger programs! With this cartridge you can plot graphic shapes, “paint” colors on the screen, easily redefine the VIC’s programmable function keys, write music ... and more.

The SwiftLink-232 ACIA cartridge replaces the Commodore Kernal RS-232 routines with a hardware chip. The chip handles all the bit-level processing now done in software by the Commodore Kernal.

PARTNER128 is a cartridge-based program that plugs into yourCommodore 128 computer, giving you access to eight convenient "accessories"...