blackboard with chalk ink
This is not super important but it would be fun. I loved the new pencil/charcoal ink and the glitter ink just for creating things. But I also found that when I'm bored studying, changing up the ink and design actually helps me find focus again, kind of like a change of environment.
That's why I would really love it if you would create a blackboard like background, with ink that looks like chalk. All of my physics and maths lectures are chalk on blackboard (although it's more greenish than black), and it would give a great feeling if my notes looked the same, and also give a little boost when you just want to give up on your problem sheet. :)