Just because it doesn't seem to have been stated yet...Tea really isn't so bad. Certain teas..I choose against anything with food dyes, or, well, valerian root. Great for what its worth on its own but when smoked seems to burn the mucous membranes (have heard valerenic acids (sp?) are cytotoxic).
As stated, lemonbalm, damiana, and passionflower are all nice fillers, yes, some even with psychoactive effects. Of debated psychoactivity would be sage..have tried, wouldn't exactly recommend...but should be fine.