Herbal teas (and floral teas) are actually called "tissane." Tissane is not really tea, as it is not caffeinated. However, many people call it "tea" anyway.
A few examples of tissane are:
peppermint "tea"
jasmine "tea"
chrysanthemum "tea"
As you can see, the plants mentioned above do not have caffeine.
Only caffeinated teas are REAL teas, which are:
Green tea
White tea
Black tea