What is the Cypher System
The Cypher System is a setting-agnostic tabletop role playing game system designed by Monte Cook Games. It's less crunchy than D&D while still having a bit of math for the nerds in your party. Setting agnostic means it can be played in any setting and still make sense. You supply the story, Cypher is the mechanics. If building a whole new world isn't up your alley, then you can always try one of the currently published settings.
Old Gus' Cypher System Reference Document (OG-CSRD) aims to be an easy-to-use reference when running or playing a Cypher game.
The Cypher System Rulebook is a thick tome with a lot of stuff in it, but as it's setting-agnostic not all of that stuff is needed. You won't need any of the space or robot stuff if you're doing a fantasy game, for instance. That's where the OG-CSRD comes in handy. Ctrl + F your problems, or use the swanky hyperlinks. It's easier to navigate than the PDF version of the rule book, and it doesn't take up shelf space.
Settings
Monte Cook Games has released a number of settings. These add flavor to the base system and turn it into a full game. Most have a few premade adventures included to get you started. All settings require the Cypher System Rule Book (or OG-CSRD) to play.
Godforsaken - Sword and Sorcery
The Stars Are Fire - Sci-Fi and Space
Stay Alive - Spooky Horror
We Are All Mad Here - Alice in Wonderland Flavored
Claim the Sky - Modern Hopeful Superheroes
The Origin - Modern Gritty Superheroes
Unmasked - Eighties Dark Superheroes
First Responders - Exactly what it sounds like
Gods of the Fall - Celestial Fantasy
Predation - Time Travel and Dinosaurs
Stand Alone Games
There are also a few TTRPGs running on the Cypher System. Some are published by Monte Cook, others are licensing the system.
The Strange - You're basically an MTG Planeswalker
~~Old Gods of Appalachia - Eldritch Hillbillies~~
Vurt - Cyberpunk with questionable intimacy
Shotguns and Sorcery - Fantasy Noir
Upcoming Games
These aren't out yet, but the hype is real. It's Kickstarter and some untested creators, so bear with them.
Old Gods of Appalachia - Eldritch Hillbillies
Tidal Blades 2 - Fish, people, and fish-people
Harrow: The Blighted Plane - Burning Man Crystal Punk
Ptolus - Much loved, much less pronounced
And Many More
I mean, probably. I don't know everything, so feel free to add to the list.
Edit: I'm from the future and forgot that Old Gods of Appalachia isn't out for y'all yet. Fixed