With the passage of time, it gets harder to find peripherals for your vintage computer needs. So increasingly we look to other solutions to keep our favourite tech in use. The RetroMouse, an open-source USB adaptor, converts any PS2 optical mouse to an Amiga/Commodore compatible one. This should give you access to heaps of cheap, available mouse options.
Currently, the RetroMouse adaptor is compatible with Amiga and Commodore 64 systems with the adaptor auto-detecting which type of machine it is connected to. C0pperdragon indicates that they are working on adding Atari ST compatibility in the future.
It’s fully open-source hardware with the schematic and PCB layouts available in KiCAD format. You can tinker with the firmware on the ATtiny1604 using the Arduino IDE and the megaTinyCore bootloader. There is more information over on the RetroMouse Github repository, including a mention of a useful function! If you want to emulate 2 paddle inputs, as if perhaps playing a game of Arkanoid, you can enter this mode by holding down the right mouse button and clicking the left mouse button 5 times! You can return to the standard mode by repeating the action with 6 mouse clicks. We love this project and are constantly inspired by the work the Tindie community puts into keeping these retro computer systems useful and functional!