RPG GRAPHIC DESIGN THAT RULES....
If your dungeon isn't more complicated than this, don't make it more complicated than this.
Also worth mentioning with Stonehell are the One Page Dungeons
This one isn't perfect (Where are all the entrances? Also, I kinda get lost in the black lines a bit) but in general the OPDs show the right instincts and learned from Stonehell and its ilk.
CALL OF CTHULU CHARACTER GENERATION
MARVEL SUPER HEROES RPG (FASERIP) UNIVERSAL TABLE
DOCTOR DOOM'S CASTLE
OLD SCHOOL HACK
Let it not be said that all you have to do to impress me is cram a lot of stuff into a tiny space. (Write your own porn joke here.)
There are also good reasons to spread out and take your time, especially when you're laying out the rules of the game. Old School Hack does it in style....
REALMS OF CHAOS: SLAVES TO DARKNESS AND REALMS OF CHAOS: LOST AND THE DAMNED
Unlike most of the examples here, the genius of the design here isn't about efficiency or ease of use--instead the RoC books achieved something many high-end RPG books consistently try and fail to do: look like impressive grimoires of ancient knowledge.
The reason these other games fail is they don't have GW's amazing stable of artists, the artists they do have don't have a sort of within-a-stone's-throw-of-Albrecht Durer style and they usually try to use way too many computer tricks like layering which no incunabula ever had.
And Adrian Smith draws the borders. You can't compete with that.
CARCOSA'S HEX DESCRIPTIONS AND PDF DESIGN
Carcosa has some obvious mistakes (tables that have a few orphan lines spilling onto the next page, information about tables in paragraph form that could easily be incorporated into the tables) but no hex product has ever done better.
WARHAMMER 40K RPGs ORIGIN PATH CHART
You're making me take time out of the game to do group character generation? Make it fun.
THE QELONG MAP
With one glance the GM can not only say what's in the hex and what the nearby landmarks are but actually describe the journey using only the map: "as you leave the dense jungle that lines the coast, the jagged edge of a crater lake is visible across a razor-straight river."
WARHAMMER 40k ORIGINAL ROGUE TRADER VEHICLE DAMAGE DIAGRAMS
There's a blueprint of the vehicle and you dropped the dice directly on it to see where you did damage.
SOME EMBARASSING MOMENTS IN THE HISTORY OF RPG GRAPHIC DESIGN...
AD&D spells- This spell is identical to the Druid spell of the same name on some other page which page? Ha whatevs some page I don't care.
3.5 character classes- How many hit points does a 3.5 ranger get per level? Fuck you we buried it under 8 feet of paragraphs, that's how many. Luckily the SRD exists.
3.5 monster statblocks- Asking a 3.5 statblock how much damage a troll does is like when you ask your grandmother where she got her hat and then she starts off explaining how your Aunt Chloris was in Poland and owned a bean farm and most of the children in the neighborhood had gout and so she went to talk to a goat and...
4e character generation- PCs that can fit on one piece of paper spread out over 4 pieces of paper (probably more elegantly than I did it), character generation pages that don't actually show you how to generate a character. A fine example of how making a game look expensive isn't the same as actually doing the goddamn graphic design.
All official D&D character generation ever- Flowchart, guys. How hard is that? Make a goddamn flowchart with little pictures of dwarves and dice.
Keep on the Borderlands- It's how many pages long? And 80% of it fits on 4 pages.
Most Story-Game-style RPGs except 3:16 Carnage: Pictures? What for, we already have white space? Can't we just use stock art? Let's just use stock art. If you ever wondered where Mark Rein-Hagen would be without Tim Bradstreet or where Neil Gaiman would be without Dave Mckean and Mike Dringenberg, check out whatever's hot on Story Games this week.
WOTC dungeons- Yes, here's another dungeon where the mind flayer isn't smart enough to leave the library no matter how much noise you make killing the giant crashing chandelier golem in the parlor because we can't figure out how to fit more than one room on a page.
Night's Black Agents character gen- You don't actually have to read a whole chapter to make an NBA PC.
D20 Versions of old Judges' Guild stuff- Your players will never find the lost empire of the dragon turtle kings because you will never find it. Because the book is too busy telling you the population of the village near it is 17% cave-hobbit and their main agricultural product is buckwheat. And telling you in paragraph form.
SOME PROBLEMS THAT NEED TO GET SOLVED
Character sheet as character generation guide: This can't be that hard. One page, everything you need, all the relevant results. Maybe two pages. Still: worksheet. Figure it out.
Weapons: Every single weapon in a game has concrete advantages and disadvantages (that's why they were invented). A new player should be able to look at a one-page array of items and instantly see both the available variety and what each thing's plusses and minuses are without being a gunporn fanatic. Prices don't have to be big, ok?
Visual index of monsters: By habitat, by level, and/or by type. Lots of little pictures, grouped together in one picture in ways that would be useful to a GM mid-game at a glance.
Visual Index of anything else GMs need to pull out of their ass at a moment's notice: Countries, plot hooks, villains, stock NPCs, etc. A big picture of, say, all the possible class/race combinations in a given setting would be useful to have, or of common trap types or spells.