SEDs
 immediately show AGNs dont look like stars
 
 Multi-wavelength
 works (e.g., radio, X-ray, IR, plus optical)
 E.g.,
 FIRST Bright Quasar Survey 
 Also
 possible to find via
 Variability
 (e.g., MACHO)
 Proper
 Motion (or lack thereof, unbiased but tough!)
 Grism
 Surveys (e.g., Large Bright Quasar Survey)