Mine is nearly a hundred pages and growing.
I give rules for the basics like character generation (Abilities, Concept helps, etc)
Also laws against rules lawyering, metagaming, munchkinisms, tardiness, and game disruptions.
New Mechanics: Luck & Perception Dealing with how to add new these new abilities to a character and a paragraph for each telling how they are to be used.
Reputation: Taken from an OGL source the full rules about using reputation in my setting.
Faith: Like reputation I have a set of rules for Faith, and the uses of faith.
Races: A small paragraph about each race followed by the Racial traits with three races being fully detailed as per the PHB
Old core classes (a paragraph or two describing how the fit into the world)
New Core Classes (full class with a paragraph about how they fit into the world)
Rules on Players writing their own classes
Equipment: New equipments, armor, and weapons that are found in my setting (including some unusual things like gunpowder weapons, and the few rarer weapons like the AK-47 which is not a purchased weapon but found near a gate (maybe). )
Skills: New uses for old skills, and New SKills Gambling (by type) (Lck), Seduction (Cha), Read Language (Int), Trailblaze (Wis)
Feats: A large master list of feats that are allowed in the game, with a 38 page section of new feats from various boards, and writers.
Spells: 23 pages of new spells
World Guide
20 Pages about the world in general, with city stats, and NPC's from every major kingdom and city, as well as a fully fleshed out port where the party comes together.
10 Pages on themes, discussing the potential thematic elements of the various sessions including, Seafaring, Urban Adventure, Dungeon delving, horror, sci-fantastic twists, epic battles, Tournements, Espionage, and Political Manuevering among others.
Followed by a Character Sheet of my design, a Character Planner, a Characterization sheet that is filled out by the players each session based off of how they think they did in certain subjects, A Map of the region they start in, and a $2 off coupon for a pizza parlor in town.