There is a great big library which is, coincidentally known as the "Great Library" hehe.
You can take a portal there from blackford castle (the library is on east server, the portal was set up by player action so that the knowledge was accessible by all.)
Theres also large libraries in the temples of Aragen, though you often have to jump through loops to get to see the good (rare) stuff, something really rare is CDQ material.
More common well known things you can surely RP knowing about, especially if your char has a good lore. Large important history are things that would be recorded at least vaguely in many locations. A semi-knowledgable commoner could know that Raiklin the great Diamolar was the greatest emperor of dregar, and that he was the last of his line, and that his reign ended suddenly when he died. Though how he died and especially who killed him and what said killer might have gone on to become are much rarer bits of knowledge. Things like that you'll have to find out from other players or from DM played NPCs.
