I was not a big Twitter user, so this may have been possible there as well, but...
I have been really enjoying the ability to create my own user Lists, and then being able to pin them to my Feeds. I have one for Astro, one for Web Dev, etc.
The next feature that I really want to see is the ability to move all users in a Starter Pack directly into one of my own Lists. That's a nice way to 10x my list size by interest group. The coolest thing is that I just created a decent feature request for that, and I know it will at least be considered.
Interest groups are something that I have realized is why I still come back to Reddit a lot. Nothing else does that as well as Reddit. While big Bsky Lists are not the same thing, it does scratch that same itch.
I could imagine user curated Lists becoming a bigger thing on Bksy, as far as finding other user's great lists and pinning them to my own feeds.