After much research I found that the moveset with the widest coverage is: FIGHTING, DARK, ICE, GROUND. Covering 14/17 types. (all but water, fighting, and bug)
Scrafty is one of the only Pokemon that can be easily obtained and acquire this set without extensive breeding.
My Scrafty knows:
BRICK BREAK: in learned by level up, nice damage and not as risky as Hi Jump Kick which causes Scrafty to lose 1/2 his max HP if he misses.
CRUNCH: solid physical dark move learned by level up.
DIG: solid, two turn, ground move learned by TM found early in the game (route 4 in BW2). And only ground type attack Scrafty can preform.
ICE PUNCH: best physical ice attack in the game. Can be aquired in Driftveil City through the move tutor in the house west of the pokécenter for 10 red shards (BW2). Also covers his flying weakness.
Without this moveset it's a waste of a Scrafty's coverage advantage.