There are many Matrix Game web pages. Some are related to professional games done by armed forces, some are hobby related.

Professional Pages

Wargame Developments

Wargame Developments Matrix

Paxsims

Mapsymbls

A Short History of Matrix Games

History of Wargaming Project

Defense Linguistics

Pellegrino: Introduction to Matrix Games 2020 Video presentation on how to play Matrix Games

Professional Publications

Modern Crisis Scenarios for Matrix Wargaming

Matrix Games for Modern Wargaming Developments in Professional and Educational Wargames Innovations in Wargaming Volume 2

Matrix Game Construction Kit

Hobby Pages

An Interview with Chris Engle

Board Game Geek Wiki

Engle Matrix Games Cthulhu Wiki

YouTube Videos of Engle Matrix Games

Story Games

Noble Knight List of Hamster Press Products

Wargame Vault PDF games

Board Game Geek page on Hamster Press

Drivethru RPG List of PDF Matrix Games

Beer and Board Game Video of Mongolian Goat Rodeo