Wonder Twins: Adjustable Crescent Wrench and Channel-lock Pliers
The adjustable crescent wrench is one of the do-it-all powerhouses in your toolbox. The sliding jaw of this wrench allows it to accommodate a range of sizes of nuts and bolts -- it's designed to be used with square and hex nuts -- which means it's good for everything from automotive repairs to household projects.
A pair of channel-lock pliers can cover the bases the adjustable crescent wrench can't; these pliers are also happy to moonlight as a clamp or a wrench if needed. They can be adjusted to objects of ranging sizes because these pliers have jaws that slide open and that can be locked into place, which is good for working on everything from a plumbing project to simply tightening a loose bolt.