Option to highlight comments made the past 15 minutes (in lieu of highlighting unread comments, as I understand that's not technically possible)

Option for a clearer distinction on who is the OP of a thread. I often don't notice the small icon, and it's useful information to have for context. Some other apps have a colored background behind the username of the OP, which I find helps a lot.

Different font colour on the "(X new comments)" on a post to better draw attention to posts with new comments

Option to have a different font colour on pinned posts to help them stand out, especially useful for communities with lots of pinned posts, or to find stuff like announcements and weekly discussion threads in your home feed easier

Support for Atkinson Hyperlegible font as an accessibility option