  We present the final observations of a complete sample of 37 radio galaxies
from the Third Cambridge Catalog (3C) with redshift <0.3 and declination <20
degrees obtained with the VLT/MUSE optical integral field spectrograph. These
data were obtained as part of the MURALES survey (a MUse RAdio Loud Emission
line Snapshot survey) with the main goal of exploring the AGN feedback process
in the most powerful radio sources. We present the data analysis and, for each
source, the resulting emission line images and the 2D gas velocity field.
Thanks to such an unprecedented depth these observations reveal emission line
regions (ELRs) extending several tens of kiloparsec in most objects. The gas
velocity shows ordered rotation in 25 galaxies, but in several sources it is
highly complex. We find that the 3C sources show a connection between radio
morphology and emission line properties. In the ten FRI sources the line
emission region is generally compact, only a few kpc in size, and only in one
case it exceeds the size of the host. Conversely, all but two of the FRII
galaxies show large-scale structures of ionized gas. The median extent is 16
kpc with the maximum reaching a size of ~80 kpc. There are no apparent
differences in extent or strength between the ELR properties of the FRII
sources of high and low gas excitation. We confirm that the previous optical
identification of 3C258 is incorrect: this radio source is likely associated
with a QSO at z~ 1.54.
