"Varying from past updates to some of the best threads these forums had to offer in a past time. If you believe your thread should be archived, please private message one of our staff. In order for us to archive your thread, it must have made an impact on the community and needs to be of old age." (copy/pasted from the archives description lmao)
All sorts of things go there, especially guides and ideas that might make their way into the game. The one thing they all have in common is their age.
If you specifically want to see guides, this should come in handy. Otherwise, the archives category includes everything.