  We explore the potential of the ongoing Zwicky-Transient-Facility (ZTF)
survey for studying Intra-Night Optical Variability (INOV) of active galactic
nuclei (AGN), in particular for picking rare events of large INOV amplitudes,
whose detection may require extensive temporal coverage. For this, we have used
the available high cadence subsets of the ZTF database to build a well-defined
large sample of 53 blazars (BLs) and another sample of 132 radio-quiet quasars
(RQQs), matched to the blazar sample in the redshift-magnitude plane.
High-cadence ZTF monitoring of these two matched samples are available,
respectively, for 156 and 418 intranight sessions. Median durations for both
sets of sessions are 3.7 hours. The two classes of powerful AGN monitored in
these sessions represent opposite extremes of jet activity. The present
analysis of their ZTF light curves has revealed some strong INOV events which,
although not exceptionally rare for blazars, are indeed so for RQQs, and their
possible nature is briefly discussed.
