One that I’d like to see is a more in-depth sorting option for posts (allowing you to see for example top of December 2020, or top of a specific day). A custom date range selection would be best. I remember this being a frequently requested feature in the early days of reddit, and they never implemented it.
The default lemmy theme uses your browser / OS settings from
prefers-color-scheme. Luckily a lot of browsers are starting to use this now.