I found an interesting thread about list of 4 player games, here is the 'summary'
Super Skidmarks (8 players with serial linkup) dl cars on aminet
Blitzbombers, Max Rally and Kickoff2 seems to support it,
Bratwurst - on aminet
Master Blaster 2 - on aminet, Dynablaster, Bug Bomber
Minerunner - Loderunner aminet
Monsters of Terror AGA
Poweroids - Asteroids with 4 players.
AirTaxi, on Aminet
Viper (on aminet) is a fun multiplayer snake, keyboard only
6-Tris - Tetris, but for up to 6 players.
are there more?
I think that some games used different/special pinout, or do they all use the same adapter?