We can see that some of the badges like Great Answer, Populist, Reversal, Unsung Hero have never been awarded. The Requirements for Great Answer is good, for others it is a bit fictious. Like for Reversal, if questions get negative votes then most probably the user will remove it or the community will. there is low chance that anyone has good answer. and seemingly less is the chance of answer scoring 20.
For Populist, the accepted answer has to have score of 10, which means it is a nice answer and useful to others as well. Then the other answer has to get 2x that means atleast 20 score. I see very low possibility that such an answer can come and even it it comes it should be the accepted answer. There is a possibility is one person gives a nice answer and anether gives gives good answer ( explaining concepts, otherwise it won't get 20) but it looks like practicably unreachable.
It says Gold badges recognize important contributions from members of the community. They are rarely awarded. but the limits should be reachable.