My flavor niche has been coffee flavors from several different e-liquid vendors. I also vape a lot of fruit and spice flavors: Apple, Lemon-Lime, Orange, Mango, Watermelon, Peach, Grape, Cinnamon, and Vanilla. Either Cinnamon or Rum added to a fruit flavor is nice, too. Adding menthol or Koolada adds some "cool factor" to fruit flavors.