In no particular order, categorized as either Philosophy, Advice, Design, Resources, or Games.
Explanation as to why geek communities are always overrun by creeps and villains.
Old school explainer from 2008. Much of the advice is quite wrong and not relevant to modern readers.
Newer old school introduction by Ben Milton & Steven Lumpkin. Better than you may expect.
Five-part series detailing the full history of the old school renaissance.
An imperfect attempt to categorize D&D play cultures interesting for the historical perspective.
Heartbreakers: knock-off D&D systems created by hobbyists whose preferences run contrary to good design.
Terminology for describing whether a supplement is useful or not.
Do referees control the direction of the game, or do players? 4 possible resolutions to the conundrum.
Callout of rules lites and fake rulesets that do not function unless the reader already knows D&D.
David Sirlin explores what it means to play to win, as compared to the scrub who does not do so.
Long-winded analysis of old school dungeon crawling.
Examination of the special role that Death plays in roleplaying games.
Semi-interesting discussion of old school XP, including several very dumb commenters who don't get it.
Why earnestly describing content is better than applying the flawed trigger warning concept.
Advice for Referees
Seminal discussion of old school play focused on OD&D. Also available in HTML.
The idea that good old school play preferences first preparation, then rules, and lastly rulings.
All around practical advice for running any type of dungeon.
Arnold K examines of how the rules interact with diegetic problem solving.
Practical advice for ensuring that game activities matter.
Hack & Slash makes an early attempt to discourage illusionism.
Rients gives some advice on running awesome games by emphasizing player engagement.
Rients argues in favor of just playing the damn game instead of worrying so much about what system is used.
Chris McDowall explains how he runs Into the Odd, advice which is applicable to many games.
Techniques for improving your dungeon maps.
Exhaustive analysis of resource management within D&D.
A quick broad overview of what it takes to run a sandbox game, written by Melan.
Simple guide to designing hex crawls written by Melan.
Blogpost describing three ways of using a hex crawl.
Article describing the benefits of using six mile hexes.
Ensuring that skill usage has consequences.
Exhaustive analysis of ability score design in adventure games.
How various spells affect the resource management aspects of D&D.
Read various books from Appendix N, for free and online.
Tool for generating medieval demographics, also available as a PDF.
List of English prices for a variety of goods during the medieval period.
Deep dive into middle age villages, including how to use this information in D&D.
Calculator for D&D demographics created for 3rd Edition but may be useful to any game.
An extensive guide on how to communicate room dimensions succinctly when players are doing the mapping.
Twenty quick questions to establish the most important details of a campaign setting.
A quick look at the first line of every edition of Dungeons & Dragons, without comment.
Google Sheet listing all monsters across a huge number of games and which appear most frequently.
Compilement of items found within products by or related to 1st and 2nd edition D&D.
An exhaustive list of retroclones, although it is unclear when it was last updated.
Comprehensive OD&D retroclone. Easily searchable due to being a single HTML document.
A variety of adventures written for 2nd Edition D&D.
An online SRD containing many of the rules for an AD&D retroclone.
An online SRD for Old School Essentials, an exact B/X retroclone.
Rare magazine containing the Code of the Rats adventure.
Wargame developed in the 1960s by the US Army for research into guerilla warfare.
Review blog with an ensemble cast selected for political views.
Due to the ensemble cast it will be difficult to contextualize any given reviewer.
Reviews nearly everything at a prodigous rate, leaving the quality of individual reviews in question.
Interviewed in a blog and video by Patrick Stuart. Plays about 2x per week in a home game & store group.
Loquacious Dutchman who reviews a wide variety of old school modules, new and old.
Began playing with 2nd Edition, Dark Heresy, and B/X. Penchant for the gonzo.
Milquetoast reviewer who exactingly describes products rather than give any actual opinion. Known also as "the poor man's Trove" since his high-def camera reveals every page of what he reviews. Joined the hobby in 2013 running games for young school children. Maintains his own list of interesting links.