  The regular monitoring of flat-spectrum radio quasars (FSRQs) in
$\gamma$-rays by Fermi-LAT since past 12 years indicated six sources who
exhibited extreme $\gamma$-ray outbursts crossing daily flux of $10^{-5}$
photons/cm$^{2}$/s. We obtained nearly-simultaneous multi-wavelength data of
these sources in radio to $\gamma$-ray waveband from OVRO, Steward Observatory,
SMARTS, Swift-UVOT, Swift-XRT, and Fermi-LAT. The time-averaged broadband
Spectral Energy Distributions (SEDs) of these sources in quiescent states were
studied to get an idea about the underlying baseline radiation processes. We
modeled the SEDs using one-zone leptonic synchrotron and inverse-Compton
emission scenario from broken power-law electron energy distribution inside a
spherical plasma blob, relativistically moving down a conical jet. The model
takes into account inverse-Compton scattering of externally and locally
originated seed photons in the jet. The big blue bumps visible in quiescent
state SEDs helped to estimate the accretion disk luminosities and central black
hole masses. We found a correlation between the magnetic field inside the
emission region and the ratio of emission region distance to disk luminosity,
which implies that the magnetic field decreases with an increase in emission
region distance and decrease in disk luminosity, suggesting a disk-jet
connection. The high-energy index of the electron distribution was also found
to be correlated with observed $\gamma$-ray luminosity as $\gamma$-rays are
produced by high-energy particles. In most cases, kinetic power carried by
electrons can account for jet radiation power as jets become radiatively
inefficient during quiescent states.
