Sallen-Key, and VCVS filters (low sensitivity to component tolerance) State variable filters and biquadratic or biquad filters Dual amplifier bandpass (DABP) Wien notch Multiple feedback filters Fliege (lowest component count for 2 opamp but with good controllability over frequency and type) Akerberg Mossberg (one of the topologies that offer complete and independent control over gain, frequency, and type)