We present a narrowband [O III] imaging survey of 111 AGN hosts and 17merging-galaxy systems, in search of distant extended emission-line regions(EELRs) around AGN (either extant or faded). Our data reach deeper thandetection from the broadband SDSS data, and cover a wider field than some earlyemission-line surveys used to study extended structure around AGN.Spectroscopic followup confirms two new distant AGN-ionized clouds, in themerging systems NGC 235 and NGC 5514, projected at 26 and 75 kpc from thenuclei (respectively). We also recover the previously-known region in NGC 7252.These results strengthen the connection between EELRs and tidal features;kinematically quiescent distant EELRs are virtually always photoionized tidaldebris. We see them in ~10% of the galaxies in our sample with tidal tails.Energy budgets suggest that the AGN in NGC 5514 has faded by >3 times duringthe extra light-travel time ~250,000 years from the nucleus to the cloud andthen to the observer; strong shock emission in outflows masks the opticalsignature of the AGN. For NGC 235 our data are consistent with but do notunequivocally require variation over ~85,000 years. In addition to these verydistant ionized clouds, luminous and extensive line emission within fourgalaxies - IC 1481, ESO 362-G08, NGC 5514, and NGC 7679. IC 1481 shows apparentionization cones, a rare combination with its LINER AGN spectrum. In NGC 5514,we measure a 7-kpc shell expanding at ~370 km/s west of the nucleus.