I was thinking about the Wizard and his spellbook. I was trying to think of another class that has a book. I thought of the Circle of the Stars for the Druids and Pact of the Tome for Warlocks. All of which are spellcasters. This made me think, how would a martial class would work if they had to refer to a book. My basic idea is that a fighter would have scrolls with fighting styles on them. The fighter would pick their normal fighting style at level 1, but at level 3 they can pick 2 more. But they can only use one of their 2 new fighting styles. So every long rest they could switch. In the player's handbook, there are 5 fighting styles, but there are 5 more options in TCoE. Lets say that a 20th Scrollmaster can have 1 fighting style they remember like every other fighter and 4 fighting styles on their scrolls, which they can use 2 of and maybe as a bonus, can switch on a short rest. I still need some additional features, but the basic idea is there. It should be a very flexible subclass, so if you are going to just keep the same fighting styles prepared, the change at a short rest thing is useless.