A Master has secrets – schemes within schemes – bluffs and counter-bluffs – and probably a lot of scribbled down half-formed ideas that read “SEXY GOBLIN?” and things like that.
If you want to convince those feckless players of your ineffable majesty and not let them see all the smudged biro notes about goblins, you should consider purchasing the official DIE RPG Gamesmaster’s screen. The front side is all Stephanie Hans, with a triptych of three original art pieces featuring a moody armoured hand, a mysterious tattooed hand, and the conflagration of possibility that lies within your soul (represented here by a flaming D20). The back is all Kieron Gillen, and as well as the standard rules summary you’d expect to find on any GM screen, there’s also:
D20 motivations for NPCs so players can manipulate and exploit them
Prompts designed to engage every class at the table
Omens of Doom with which to threaten the players
A grab-bag of adversary stats, in case you need to have a fight on short notice
Lists of Standard Fantasy Tropes and Standard Real-World Tropes you can combine ad-hoc to look like a creative genius
Minerva McJanda (Heart, Lancer, Voidheart Symphony) did the layout, and Grant Howitt (Spire, Heart, Honey Heist) fudged the words around a bit and added some new ones, so you know it’s good. It comes printed on nice thick card, it’s landscape rather than portrait orientation (so you can actually see and talk to your players) and it even has a reminder of which class has which dice along the top in case you completely forget.