You could be thinking of
Poppins. It was a great mod but I don't think there's a working version now (I could be wrong). Poppins was mostly used for a totem bar so when it was added into the game I think the demand for poppins dropped off.
There was also
Klappa 2, not sure if it works either as it was last updated over a year ago.
I can't think of a currently active mod that has popups in quite the same way.