Guides by people. In case flooding your brain with an entire comprehensive wiki of information just overwhelms your brain and you need someone to explain what to do with all that.
Monstrous Advice: A guide by wikimonster. (Start, Early and Mid game)
Sagefault's Endgame Guide: Crossing the gap between Monstrous and Hogla. (Mid - End game explained)
Avian Advice: A guide by... someone. They didn't say their name. A birb, presumably. (Outdated... and bad anyway, best to just ignore this entirely)
Apocrypha: A small, community article on faith resetting and OotS. (Order of the sun explanation, TT)
When to Upgrade: Answers to the frequently asked question of when it's better to upgrade buildings.
Math Hacks: Optimizing resets and stuff using math!
Relic Engines: Additional math behind Relic Engines
The Noob's Guide to Kittens: For those who don't want to follow the rules, but have loads of fun.