This repo will help you do daily update blocklists, you can check https://gist.github.com/shmup/29566c5268569069c256 for detail and use https://github.com/sahsu/transmission-blocklist/releases/latest/download/blocklist.gz in your setting.
here's how to do settings.json:
add to you settings.json
"blocklist-enabled": true,
"blocklist-url": "https://github.com/sahsu/transmission-blocklist/releases/latest/download/blocklist.gz",
verify by command:
$ transmission-remote -n admin:password --blocklist-update
localhost:9091/transmission/rpc/ responded: "success"