What are your favorite GitHub actions/bots?

Hey HN, I'm going to write a blog post about bots and automation in OSS communities.

I've been doing research, but I'd love to get input from the HN community. I've been amazing at how many OSS communities build their own Github bots tailored to their needs like - https://github.com/apps/boring-cyborg for Airflow - https://github.com/jekyll/jekyllbot for Jekyll - https://github.com/apps/google-ml-butler for TensorFlow

Please share any bots or actions you think are neat!