I will go for the wild-card, gun & knife are to obvious, baseball bat, golf club & axe i would not think are readily available in all homes. A knife is but as i said it feels a little obvious but would be my answer if the question was for fatal crimes. So i say screwdriver, most homes have one.
@Deadcutie Drat yes most households would have one in the USA. NOTE TO SELF: Need to stop watching Sherlock and watch more Columbo lol or maybe Kojak ☺