From Bulbapedia, the community-driven Pokémon encyclopedia.
The Brock's Sand Pit Deck is a type deck found in the Gym Heroes Strategy Guide. The deck is classified as one of the advanced decks, containing more rare cards and strategy than other easy-to-build decks.
"Brock's Sand Pit" is a hard-hitting Fighting deck that doesn't pull and punches. The basic strategy here is to attack with everything you've got and Knock Out your opponents' Pokémon before they know what hit them. Fighting Pokémon can do a lot of damage for very little Energy, and this deck makes good use of that.
Hitmonchan is always a star, and you can use Brock's Training Method to go get Brock's Sandshrew and Brock's Sandslash to quickly play this tough mouse. PlusPowers only add to the speed of your damage. The big problem with Fighting decks is that many Pokémon have Resistance to Fighting Pokémon. Pewter City Gym makes this problem go away for all of Brock's Pokémon. There's a reason it's called the "home field advantage," and Brock knows it!