Intro

Here I've collected the best links for going down rabbit holes, if a link contains something somewhat objectionable I'll add a warning.

Basics

Reddit
Thousands of forums for probably any topic you can think of, NSFW subreddits and posts are marked as such

People looking for specific Subreddits, and people listing specific Subreddits

Exactly what it sounds like

Wikipedia
The free encyclopedia, you aren't allowed to cite it in your shitty essay for US History but you can have a helluva lot of fun on it

Fandom
In-depth wikis on almost any piece of media out there

The Internet Archive
Uploads on everything from arcade games to antique books

Knitting magazines! Computer magazines! Sports magazines! all pretty good scans too!

Games

What if fantasy games lived up to their names?

2,643 Acrade games you can play in-browser

Wikis

Wanna read about people's ideas about fictional people kissing? Well now you can do it! They even have a category for cargoships

Lots of information on Showbiz pizza animatronics and a lot of other Creative Engineering works

A fandom wiki about Animorphs!