While I like the wreath idea that JustWannaQ has given ... if you have no interest in those buttons, don't do that or heaven forbid, they will gift you with more!
Was there a time when you were looking for buttons as embellishment for a quilt? Maybe that started it?
To stop the nonsense ... my suggestion isn't so lovingly-kind as JWQs ... Put all the buttons into a bowl. Stir them up. Fill up jars with them. And give a jar to each of those who have given to you.
Think they may get the hint? :)