• Apple DOS, 1978-1983
• Apple SOS, 1980 (the Sophisticated Operating System for Apple III)
• Apple ProDOS, 1983-1993
• MacPaint, 1984-1988
• MacWrite, 1984-1994
• MacTerminal, 1984-1987
• Apple GS/OS, 1988-1993
• A/UX, 1988-1995, Apple’s version of UNIX System V
• Macintosh Portable, 1989-1991
• Apple Dylan, 1992-1995 (lives on as OpenDylan…)
• Taligent, 1992-1998
• Apple Workgroup Server, 1993-2003
• Macintosh Application Environment, 1994-1998, a $549 software package which allowed running System 7 on Solaris and HP-UX
• QuickTime VR - 1995-? …to my surprise, apparently still playable until Safari 12 in 2018
• MkLinux 1996-2002, a port of Linux to run under the Mach microkernel on PowerPC
• Apple Network Server 1996-1997 (ran neither A/UX nor MacOS but instead IBM AIX)
• Twentieth Anniversary Macintosh, 1997-1998

edit: i mistakenly listed a couple items they actually do have.

ps: anyone reading this who wants to open a github PR to add these things to the site, please do :)