Systemd by example

 https://systemd-by-example.com/

container-based playground to learn about systemd

Pack Your Bags – Systemd Is Taking You To A New Home

https://hackaday.com/2019/10/16/pack-your-bags-systemd-is-taking-you-to-a-new-home/
I still don't think this is a good idea

Setting up containers with systemd-nspawn

https://blog.mekansm.de/2017/09/16/setting-up-containers-with-systemd-nspawn/
systemd might actually be useful for something

Systemd at 3am

https://www.redpill-linpro.com/sysadvent/2016/12/22/systemd-at-3am.html
Good shortcuts for when you have to resurrect something running under systemd.