If someone made a new DND app, what would you like to see it be able to do?

Sorry if this isn't allowed, if I am breaking rules with this post please remove it mods.

I want to just for my own practice make a dnd app for my party and I to use. It will work as a character sheet, note keeper, encounter and initiative tracker, have some roll guide messages for newer players in our group to help them know what to roll.

What are some features in DND Beyond or Roll20 that stand out as oh this is great or maybe even features you think they are missing?

I'm not planning on making something commercial, this is mainly for my own coding practicing and for something my party can use but thought would be cool to also hear some people's opinions re: features.

Thank you and again sorry if on the wrong subreddit for this.