Great list. Surprisingly, I hadn't even heard of YC's most successful exit (Divvyshot, acquired by Facebook at 20M$).
ALL of the exit values (except 1 or 2) are my personal estimates and educated guesses... nothing more. I'm always happy to revise them with better information!
TechStars at least publicizes whether the exits are > or < $2million, which can be a helpful guide...
I'd bet under $10M, probably closer to $5M. Based on me sitting in my chair knowing nothing.
If your guess is no better than the reader's, I think it's best to provide the relevant information you know, and let us draw our own conclusions.
I'm about to start work as a new employee at a YC alumni, hopefully we'll do better!