That's a nice topic and question 😀
I am actually trying to locate PC lightgun games...
There were four different lightguns for PC games (and some for later Windows games).
1) French gun - called "Phaser", by Loriciel(s) (1989). Connects to a Serial port.
Only two Loriciel(s) games supported it - "West Phaser", the one it was bundled with (the 1989 edition - in the 1992 re-release they added joystick, mouse, and keyboard as well), and "Crazy Shot" (1989 as well, but this game supports mouse and keyboard from the very beginning).
There were also rumors that "Moon Blaster" (by Loriciel) and "Capone" (by Actionware) support "Phaser" as well, but I have not seen those versions yet.
download/file.php?mode=view&id=210322
2) Spanish gun - called "GunStick" (1989). Connects to a Parallel port.
There were at least five games supported exclusively, by Opera and Dinamic, in 1989: "Solo", "Target Plus", "Mike Gunner", "Guillermo Tell" and "Trigger". And two more games, "Cosmic Sheriff" and "El Equipo A", had special versions for GunStick as well.
download/file.php?mode=view&id=210319
3) US gun - called "PC Gamegun" by American Laser Games (1993?). Connects to BOTH parallel and game ports.
All ALG DOS games support it! But not exclusively: "Mad Dog McCree", "Mad Dog II", "Crime Patrol", " Drug Wars", "Space Pirates", "Who shot Johny Rock", "The Last Bounty Hunter".
download/file.php?mode=view&id=210321
4) Taiwanese gun- called "PcGun", by EMAG and A4Tech (1996-1997). Connects to a special ISA interface card.
Only three games support it, all by EMAG: "A.D Cop", "A.D Cop - Overseas Mission" and "BonBon Paradise" / "BonBon Lite".
This one is for both DOS and Windows.
download/file.php?mode=view&id=210320
I have two out of four - "GunStick" and "Pc Gun". And, well, I have very little luck with them 🙁
Only half of the games work with "GunStick" - and I can't get "Pc Gun" work at all yet. The screen just flashes when I press the trigger, no shot are visible or recognized.
So - it is not too surprising none of those guns were a big success, you know.
And as I said, there were also Windows and/or USB light guns, like PC Audo Mag or Act-Labs. But I am not familiar with those.