Hey all,
Between poking around in existing Roam themes and helping people on the #css-themes slack channel, I’ve collected a few short CSS snippets that can help people personalize their databases. Here’s a link to my blog post where I cover them. Let me know if you have requests for additions or other feedback, and add your faves below 
(Note, I’m forking from Awesome CSS for beginners and intermediates because there’s a lot going on in that thread already, but that is a great start too!)