Twist, black pepper is great, if measured right. It gives every sip and extra kick. Awesome for colds as well. Somalis I've seen go nuts, and add all those ingredients in one pot, ending up creating an insane concoction I can't get myself to drink. It doesn't even taste like tea any more.
I've experimented a bit with tea. I find nutmeg gives it a peculiar warmth. Coconut and vanilla are great, boiled with the shah and milk. Stay away from chocolate, not a good mix
I've been interested in orange zest/peels/oil, but could never get around to actually do it.