Given my own channel's branding it would be easy to do anything Japanese related such as a Crunchyroll anime spot, a cosplay/costume shop of some kind, or even to some test cutting with swords from a weaponry manufacturer. Book shops would be easy to integrate into the channel since I'm a writer and my channel's mainstay is about history. I'd love to do a branded deal with Half-Price Books or Barnes and Noble. Amazon wouldn't be a bad one to get a contract with, either.
A television show or a movie set in a Japanese historical period would be a good branded deal that I could integrate easily. For instance if Keanu Reeves came knocking I could do a 47 Ronin-related video, even if the movie sucks the important thing is that I have informative and entertaining videos out of the topic...the plus is the cash they could shower me with.
And I'm not above branding with smaller things. I am lactose intolerant but I love milk...so I drink a lot of Lactaid; if Lactaid wanted to pay me or give me free stuff, I'd totally turn the container to face the camera when I cut milk cartons. When I do sword-cutting videos I always turn the label of whatever I'm cutting away from the camera; but if they pay me, I'll turn it toward the camera.
Heck if a drink company wants to sponsor me, I can make sure their drink is in the photo or video at some points even if its just sitting within view with the label facing the camera.
As far as vehicles go...I wouldn't turn down a free Ford or Chevy vehicle, of course, but I'd rather get sponsored by Toyota. Haha.
I'm hard to shame, but not totally shameless. The bigger question is what I wouldn't hawk or promote on my channel; there are a few companies I refuse to do business with and I would outright refuse them based on moral grounds like Nestle or Best Buy, and a handful of other companies.