DnD app

Hi everyone,

I'm working on an idea for a mobile app to help with D&D campaigns. I don't play D&D myself, so I wanted to ask the community what tools or features you feel are missing.

One idea someone mentioned was a spellbook app, where you could save spells for specific characters or classes and quickly access them during a campaign.

Would something like that actually be useful during a game?
And are there any other features you wish existed in a D&D app but currently don't (or aren't implemented well)?

I'm also curious what apps people currently use. I know some players use apps like D&D Beyond, Fight Club 5th Edition, or Game Master 5th Edition. If you use any of those, what do you like about them and what do you think they do poorly or could improve?

Thanks for any feedback!