OSR Advanced Player Options

The OSR Advanced Player Options books compiles several years of material into a single book designed to expand any OSR-style game. Written for Old School Essentials, it contains the following:
Guidelines for running successful play-by-post games.
A simple skill system.
Rules for founding temples and using the divine energy that worship generates.
Rules for improving magical weapons by performing feats of derring-do.
A simple prestige class system based on rules from the BECMI Gazetteers
A bunch of new race-as-class options, including binder (from 3.x Tome of Magic), monk, necromancer, parrot-folk, and more.
Rules for researching spells and creating magical items.
Rules for ritual spells.
Dozens of new spells.
This is an A5 formatted, 336 page pdf. An offset version of the book is coming soon.