Wow that's a big number. Are the videos which aren't public yet your future uploads or are they older videos you have unlisted?
Well the majority of my unlisted videos are for the most dedicated viewers. Usually in the form of a poll for them to decide what game I play next (Using their own suggestions). Sometimes it will be bonus content like an alternate route choice in a game. Heck even failed first recordings so that way people can see my original reaction to stuff even if there is a problem with the video that required me to re-record it.
For the private videos most recent ones are archived streams I've done but decided not to make them public because of issues (Like too many dropped frames or issues with stream lag) generally these get uploaded in an unhindered version from what was saved on my computer so I just leave the archive on youtube as private.
Older private videos I have are episode segments back when I was too stupid to know how to put two clips together in editing software so I uploaded each individual segment on youtube and then used youtube editor to combine them into one episode. (Shame youtube got rid of that because I did use that for other things on some occasions.)
My oldest private videos are actually a collection of clips of me playing Tales of Symphonia trying to get footage for my "Kratos Quotes" series where I tried to upload every quote from my favorite character Kratos Aurion. Over 100 of my private videos are dedicated to just that alone.
