Ok, I'll give one away, only because it's so simple.
brooks -(dunn, garth, abercrombie)
Since people sell BB items under both "Brooks Brothers" and "Brooks Bros," this catches both. This search eliminates Brooks & Dunn items, Garth Brooks items, and a line of Abercrombie & Fitch stuff called "Brooks." Depending on what I'm searching for, I'll add something to the negative field. With shirts, for example, I include "non" to weed out the non-iron stuff. Pants, I include "pleats" and "pleated." For outerwear, I've got to add a bunch to get rid of all the leather motorcycle jackets.