ElliottForceLegacyRTC.kext
Prevents a CMOS reset on reboot without a DSDT.
EvOreboot
If you don't have a DSDT, shutdown and reboot do not work without this kext. Installed in /Extra/Extensions.
FakeSMC
FakeSMC.kext is the only absolutely mandatory kext, and is required for booting the system. Original by netkas, new branch by Project OS X. Installed in /Extra/Extensions.
NullCPUPowerManagement
Disables AppleIntelCPUPowerManagement.kext to prevent kernel panic without proper HPET DSDT edits. Installed in /Extra/Extensions.