I used to put a lot of energy in betting boxing. It's a weird market because the overwhelming majority of the time there are few lines with tiny limits. If you beat them then you get limited super quick. But... every once in a while a huge fight comes along and you can get down virtually anything you want, and the lines can be very soft.
I put in a big bet (for me) on over 7 1/2 -110 last week, but the only book where you'll find that number now is a history book.