I’m not sure you need to extract it, you can spawn bluebrints, they are really classes, which the _c tacked to the end of their name kind of indicates. I have used the SpawnActor node and in the selection box dropdown my blueprints that do extend from Actor in some way are there.
As for looping through the list of them. I’m not 100% sure, but have you looked at the Blueprint LibraryAsset?