No, not style guides that don't exist, style guides for the imagination. Yes, potentially a dick move, but hear me out.
Differences in expectation and visualization can contribute to the breakdown of a game. The way the player's visualize the game is not only responsible for a great deal of the appeal of tabletop gaming, but it is also helpful if the DM and players are on the same page. Jeff Rients had an excellent post about accommodating player's wants into the campaign, you have to fit in cyborgs, and ninjas, and gnome wizards, and so on if your players want to play them. But if you can present a coherent vision in a way that the players respond well to, you can create a stronger game- get people's expectations on the same page, and things become easier.
Just the angle at which I picture the game when I play accounts for huge differences in my character's actions. I tend to see my fighters and clerics in third person, from behind, as in a comic book. The power of the persona inspires me to acts of stupid bravery, makes retreat hard to imagine, details hard to picture.
Conversely, my thieves and warlocks see things in first person. Imagining the bugbear in your grill, and the same bugbear but with Conan-with-your-face between your mind's eye and the bugbear can change your tone and playstyle. It's easier to imagine details, straining at the dark, poring over librams and locks alike from the first person.
The same principle applies when I referee, even more overtly. I could go on, but it comes down to whether I want to focus on the SCENE, or the EXPERIENCE. You see, Vs. Grignar sees. Expectations of power and competency change when you add or subtract the mighty alter ego.
Similarly, I don't find it at all unreasonable to try to find a shared idea for the campaign aesthetic. Live action vs. Cartoon. Frank Frazetta or Terry Gilliam. Amateur line work Vs. Airbrushed titans/ Black and White or color? The referee presents a myconoid. I could see this, as a player in any number of ways, and if I am seeing Elric in front of the Tony Diterlizzi illustration, while the thief is imagining a live action, 1st person mushroom man, and the referee sees the ominous Dave Trampier picture, everyone's actions run the risk of seeming bizarre to the others.
Diversity of imagination is not a bad thing. And it is both impossible and absurd to want everyone at the table to see exactly the same thing all the time. Just the same, I'm heavily considering a check of my group's personal imagination styles. I think I'm running Marvel Conan mixed with Dali and Tales of The Black Freighter.
What are my players seeing?