Maxperson
Morkus from Orkus
The most commonly used lore check is, "What do I know about this creature?" The DC's for that sort of check for my game are DC 15 for basic knowledge like, "It's a Githyanki." DC 20 gets you detailed information like, "Githyanki have mind abilities like X, Y and Z, and some use silver magical swords." DC 25 gets rare info like the name of the Githyanki queen and other very hard information to get.Generally in most games if knowledge checks are a thing (not super crazy about them) I would expect a successful check to answer whatever question the player had about the fiction according to their established fictional positioning. I mean if you do not know what's in question how can you set a DC?
Whether that information turns out to be useful will depend on what the party has available on hand.