Maximise Q factor in low pass Sallen and Key Filter
I'm not sure why you would want to do this - and presumably you have constraints such as  the cutoff frequency and LF gain, but with an LF gain of 1 you can obtain an arbitrarily large Q (theoretically) by making C1 much larger than C2 whilst maintaining the product C1C2 to preserve the cutoff frequency. There will of course be a practical limit to both capacitor values.