  We present a flare star catalog from four years of non-targeted
millimeter-wave survey data from the South Pole Telescope (SPT). The data were
taken with the SPT-3G camera and cover a 1500-square-degree region of the sky
from $20^{h}40^{m}0^{s}$ to $3^{h}20^{m}0^{s}$ in right ascension and
$-42^{\circ}$ to $-70^{\circ}$ in declination. This region was observed on a
nearly daily cadence from 2019-2022 and chosen to avoid the plane of the
galaxy. A short-duration transient search of this survey yields 111 flaring
events from 66 stars, increasing the number of both flaring events and detected
flare stars by an order of magnitude from the previous SPT-3G data release. We
provide cross-matching to Gaia DR3, as well as matches to X-ray point sources
found in the second ROSAT all-sky survey. We have detected flaring stars across
the main sequence, from early-type A stars to M dwarfs, as well as a large
population of evolved stars. These stars are mostly nearby, spanning 10 to 1000
parsecs in distance. Most of the flare spectral indices are constant or gently
rising as a function of frequency at 95/150/220 GHz. The timescale of these
events can range from minutes to hours, and the peak $\nu L_{\nu}$ luminosities
range from $10^{27}$ to $10^{31}$ erg s$^{-1}$ in the SPT-3G frequency bands.
