You'd be surprised. I hate tea, but I love Alice in Vapeland's tea flavors. They don't have the in your face flavor like other vendors I use, but I find myself using them more than most. If you have the time to dial down perfection, DIY.
Edit- I guess I decided to include what I've used everyday..
Fuzion Vapor, Alice in Vapeland, and J-Vape's. There are a lot of great vendors though. MB has already been plugged, but vaporchef, indigo, halo, pink spot, alien visions... Those are good ones that come to mind without me having to look at a list.