I dont have any or havent really used them, but i know they could be very helpful for the Balance druid. I believe This Macro from @LazyTurtle_121949 has one in it to track everything but i could be mistaken. I know i seen one accidently when i was skimming macros for ideas for my macro.
If anything, and i know you already know this, you can go to the Balance druid weak aura page and get some good things from people that know what they are doing with weak auras. best of luck to you and sorry i couldnt be of more help.