There is a Watchtower fork. The older Watchtower has not been updated in two years.

watchtower.devcdn.net/container-selection/ By default, watchtower will watch all containers. However, sometimes only some containers should be updated.

There are two options:

1. Fully exclude: You can choose to exclude containers entirely from being watched by watchtower.
2. Monitor only: In this mode, watchtower checks for container updates, sends notifications and invokes the pre-check/post-check hooks on the containers but does not perform the update.