I've been cutting back on coffee, and have switched over to drinking mainly green tea. I don't get as jangly from drinking green tea as I do from coffee, probably because it has less caffeine than coffee, and it contains theanine, which may have calming effects.
My favorite kind of green tea is matcha, which has a stronger flavor than loose leaf or bagged green tea. Matcha is made from shade grown tea leaves that have been de-veined, de-stemmed, and ground into a fine powder that's almost fluorescent green.
It's fun to make matcha at home, but I haven't come across any places that serve it. So I bought a case of Matcha Love on Amazon ($(removed) for 20 cans). These cans contain 5.2 ounces of matcha tea, and taste good at room temperature. I take a couple of cans with me when I go out for the day. I just wish I could pack it in my carry-on bag.