Links to some useful Public Domain and Commercial Software

System Enabler for C650 Serial Port Modification
System Enabler for LCIII (P450) Speedup
System Enabler for Q605 (LC475, P475, P476) Speedup

Output Enablers' System 7.5 Updater Patch for clock chipped PowerMac 7100/66, 8100/100, and 8100/110's. This patch allows the System 7.5 Update to run on clock chipped 7100/66's, and is necessary for clock chipped 8100/100's and 8100/110's with the System 7.5 Update. The patch is not needed for any of the other clock chipped Apple Macintosh computers described here. The patch is also needed for a clock chipped Power 100.
Swedish System 7.5 Update Patch (see above).
British System 7.5 Update Patch (see above).
Wish I were... 2.0 by Martin Blitz (mblitz@ultranet.com) is a Control Panel and Extension that provide a method for a system to identify its hardware as another hardware type, via the Gestalt "mach" selector. This will not work as a trick to allow the use of the System 7.5 Update as it loads too late. This software is based on Martin's earlier Control Panel, Who am I? which was written to allow the use of MachTen on a PowerMac 6100/80. During the update it was renamed because of the name conflict with the WhoAmI? 1.3 extension by Jonathan Jacobs (jxj24@pop2.cwru.edu) listed below. Wish I were... 2.0 can also be used to get MacOS 8.5 to run on a 68040-based machine with a PPC processor upgrade card.
601 Processor Upgrade Patch by Chad Leigh (chad@xmission.com) is a patch for clock chipped Q605 (LC475, P475, P476) machines. This patch enables you to switch between 68040 and 601 modes.
Mac Identifier 2.0 by Maurice Volaski at Flux Software (support@fluxsoft.com) is a freeware control panel designed for System 7.5 (and for 7.1P) users who can't stand the thought of their Macintosh not knowing its own model designation or what itself looks like. It is also useful for network administrators who manage networks consisting of any 7.5-based Macintoshes.
WhoAmI? 1.3 by Jonathan Jacobs (jxj24@pop2.cwru.edu) is a freeware application that patches System 7.5 and later so your Mac will actually have it's real name and icon when you call up "About This Macintosh..." It now works with System 7.5.5.
Soft Pivot 3.2.1 Patch for the Soft Pivot 3.2.1 Software. The Soft Pivot Software as it comes from Radius will not work properly on several clock chipped machines including the LC475@20MHz, LC475@33MHz, Quadra 605@20MHz, Quadra 605@33MHz, PowerMac 6100/60@80MHz, PowerMac 6100/66@80MHz, PowerMac 7100/66@60MHz, PowerMac 7100/66@80MHz, PowerMac 8100/80@60MHz, PowerMac 8100/80@66MHz, PowerMac 8100/100@120MHz, PowerMac 8100/110@120MHz, Quadra 605@20MHz, and Quadra 605@33MHz. This patch modifies the Soft Pivot Driver Extension so so it will recognize your monitor.