The slow way
for file in DRB_UCA231_*201908*.csv.gz; do
rm $file
done
The faster way
ls | grep "^DRB_UCA231_.*201908.*\.csv\.gz$" | xargs rm
The second case we're using a grep regex, so we have to escape periods, so they don't match the "any char" pattern, and we also anchor the pattern at either end. I think it might be faster with the anchors, and of course, we don't get any false hits.
In either case I think I'd do some sort of backup first, just in case the pattern/glob matches things I don't want deleted!