Mailbag and Teardowns are both very popular.
Reviews do ok.
My most popular videos have been my soldering tutorials, but only because they are highly keyword indexed (keyword searching muddies the numbers after a while)
New uploaded soldering videos not so popular to my existing audience.
Some of my tutorials or more technical videos have been the least popular, surprisingly.
It's hard to get numbers on this, and you have to differentiate between videos for my subscribed audience, and videos overall based on keyword search views.