Equalizer is the name for Balance damage boon (3%), not a universal damage talent. The Equalizer jewel is the same talent (Balance only), and does not stack.
Some pets do indeed have the "boon" talent, but it is true that most pets (and two schools) do not.
It seems that several storm and ice pets, in particular, do come with this extra damage talent but others like Fire and Myth do not. Life and Death have a couple of pets each that offer the 'boon' talent.