Loggable (https://www.loggable.io) is a SaaS app, built entirely on Drupal 8, offering centralized, administrative logging (ie, watchdog) and alerting (email, slack, etc). While it can be used to provide a front and back end for anything that requires admin logging* (ie, scripts, cron, imports, deployments, etc*), through the REST API (https://docs.loggable.io), it was built with Drupal applications and environments in mind; and there is already a D7 and D8 contrib available for easy integration (https://www.drupal.org/project/loggable).
The concept is pretty simple. Whether you manage a single site, or multiple sites, each with many environments, you can connect to Loggable to offload your admin logs, be able to view everything in a single place, and configure rule-based alerts to decide who gets notified, and for which events (ie, post to the dev channel in Slack whenever an error is logged).
I hope the community finds this interesting, either as an example of the power and flexibility of Drupal 8, or as a useful solution.
Please share any feedback/questions you may have.