  In the archive of the Ground Wide Angle Camera (GWAC), we found 43 white
light flares from 43 stars, among which, three are sympathetic or homologous
flares, and one of them also has a quasi-periodic pulsation with a period of
$13.0\pm1.5$ minutes. Among these 43 flare stars, there are 19 new active stars
and 41 stars that have available TESS and/or K2 light curves, from which we
found 931 stellar flares. We also obtained rotational or orbital periods of 34
GWAC flare stars, of which 33 are less than 5.4 days, and ephemerides of three
eclipsing binaries from these light curves. Combining with low resolution
spectra from LAMOST and the Xinglong 2.16m telescope, we found that $L_{\rm
H\alpha}/L_{\rm bol}$ are in the saturation region in the rotation-activity
diagram. From the LAMOST medium-resolution spectrum, we found that Star \#3
(HAT 178-02667) has double H$\alpha$ emissions which imply it is a binary, and
two components are both active stars. Thirteen stars have flare frequency
distributions (FFDs) from TESS and/or K2 light curves. These FFDs show that the
flares detected by GWAC can occur at a frequency of 0.5 to 9.5 yr$^{-1}$. The
impact of flares on habitable planets was also studied based on these FFDs, and
flares from some GWAC flare stars may produce enough energetic flares to
destroy ozone layers, but none can trigger prebiotic chemistry on their
habitable planets.
