1541 Speed Test by Zibri - Need to diagnose an issue with your sick drive? Well here's a tool that can help.  Although it seems straight forward, I highly recommend reading the documentation, especially if you don't want to bork the disk your testing with.

It's really nice when people put out quality software and share it with the world.  1541 Speed Tester is just such a program, and it deserves some more attention.  Please visit the software project page at https://github.com/Zibri/C64-1541-Speed-Test.  I also recommend visiting the authors web page at https://www.valoroso.it/regolare-il-commodore-1541-con-speed-test-by-zibri/

Input Device Tester 64 by Pastbytes (Released Dec. 24th, 2022) - Here is a really slick diagnostic tool for C64 Joysticks (with up to 3 buttons), Analog PC joysticks, Commodore 1351 mouse (in port 1), Paddles, Keyboard and the Retropad.  

Here's a link to the release announcement over at Lemon64.

Keyboard Routine V3.0 (Released August 8th, 2025) by TWW of Creators is as far as I can tell a utility to test the keyboard on a Commodore 64.  Source code and additional information can be found on CodeBase64. Original source for the file can be found here on CSDB. 

MR TESTER is a multifunction diagnostic program that will check your system for hardware problems that may cause serious data loss or other types of hardware malfunctions. The diagnostics on this disk will test your disk drive, printer, keyboard, screen, SID music chip and many more hardware related functions. MR TESTER is easy and fun to use because it was written for maximum user friendliness. Please read this instruction booklet before embarking on ‘checking out’ your C-64.

Manual can be found HERE!

Sound 47 by Frank7 - Although I have this in the hardware testers category, it's probably more of a demo of the SID chips capabilities, either way, it's pretty neat to hear what the little sound chip can do.

Stepper Test is a program for the Commodore 64 that will exercise the stepper motor on a 1541 floppy drive and let you know if it has issues.