How about some real cream?
It doesn't take much ... and being the real thing, it is much healthier for you than some of the other options.
For my tea ... I like it black and the stronger the better, so no help there for the add-ins.
There's always lots of herbal and other sorts of teas which can give you oh so much flavour, and not be a regular plain black tea. Again, I don't add to those either.