One of the things I love about D&D is the extent to which some folks are willing to go to build out the existing lore.
Here are a couple sites I circle back to:
- This one is awesome. If you guys ever want to know how I plan to fight a certain monster, look no further.
http://themonstersknow.com/
- An interesting site mostly built around this guy's 9 billion word screeds, filled with censored expletives. He makes good points about DMing but you have to shift through all the crap to get there.
https://theangrygm.com/