All i did to add to my lists was to go to the Bryce's preset/objects folder and right clicked with mouse and chose 'New folder', did this 10 times and changed the names to suit what I was going to save, ie; Buildings, Sci-fi, terrains and so on......when opening up Bryce, all the folders were there waiting for me to fill.....that was it. When you want to save any object select as normal from the 'Create' which opens the models, select the bottom left hand drop down arrow and choose your folder to save in.

Smile, your dead a long time :)