  Cadmium Zinc Telluride Imager (CZTI) aboard AstroSat has been regularly
detecting Gamma-Ray Bursts (GRBs) since its launch in 2015. Its sensitivity to
polarization measurements at energies above 100 keV allows CZTI to attempt
spectro-polarimetric studies of GRBs. Here, we present the first catalog of GRB
polarization measurements made by CZTI during its first five years of
operation. This presents the time integrated polarization measurements of the
prompt emission of 20 GRBs in the energy range 100-600 keV. The sample includes
the bright GRBs which were detected within an angle range of 0-60 degree and
120-180 degree where the instrument has useful polarization sensitivity and is
less prone to systematics. We implement a few new modifications in the analysis
to enhance polarimetric sensitivity of the instrument. Majority of the GRBs in
the sample are found to possess less / null polarization across the total
bursts' duration in contrast to a small fraction of five GRBs exhibiting high
polarization. The low polarization across the bursts can be speculated to be
either due to the burst being intrinsically weakly polarized or due to varying
polarization angle within the burst even when it is highly polarized. In
comparison to POLAR measurements, CZTI has detected a larger number of cases
with high polarization. This may be a consequence of the higher energy window
of CZTI observations which results in the sampling of smaller duration of burst
emissions in contrast to POLAR, thereby, probing emissions of less temporal
variations of polarization properties.
