We presenting some results for brightness variabilty in optical range for blazars, which were proposed as candidates by academician N.S.Kardashev with colleagues about two decades ago.
The intensive studies using 1-m class telescopes of SAO RAS, allowed us to discover a numerous manifestations of flux variation on timescales from minutes to months.
Together with some results published by us earlier, we present new ones, not published yet.
The opening for observations of SAO RAS small telescopes complex provided us multiple increase of observing facilities.
As a result of this development we can detect many local and global brightness maximae for these violent variable sources as well as intra-day variations phenomena too.