  We have detected 27 new supernova remnants (SNRs) using a new data release of
the GLEAM survey from the Murchison Widefield Array (MWA) telescope, including
the lowest surface-brightness SNR ever detected, G0.1-9.7. Our method uses
spectral fitting to the radio continuum to derive spectral indices for 26/27
candidates, and our low-frequency observations probe a steeper-spectrum
population than previously discovered. None of the candidates have coincident
Wide-field Infrared Survey Explorer mid-IR emission, further showing that the
emission is non-thermal. Using pulsar associations we derive physical
properties for six candidate SNRs, finding G0.1-9.7 may be younger than 10kyr.
60% of the candidates subtend areas larger than 0.2deg$^{2}$ on the sky,
compared to $<25$% of previously-detected SNRs. We also make the first
detection of two SNRs in the Galactic longitude range $220^\circ-240^\circ$.
