Apple Support - Mac OS X keyboard shortcuts

Apple Support - Mac startup key combinations

Equivalent to Apple keys on a Windows keyboard:

Boot the machine while holding down the 'c' button.

Boot the machine while holding down the Option button.

Press and hold the F12 key while booting.
Press and hold the left mouse button while booting.

Source: iClarified - How to Eject a CD From Your Mac Using a PC Keyboard or USB Mouse

Boot the machine while holding Command+Option+P+R, wait until you hear the chimes a second time before letting go.
Apple Support - Resetting your Mac's PRAM and NVRAM

Boot the machine while holding down Command+Option+O+F.