Individual and sets of adjustable spanners

Multiple uses.

General as well as specialist wrenches for removing filters.

Wrenches specially shaped for engine water cooling pumps. (See also the 'Cooling System' category for many other tools)

Self-locking grips, sometimes called Mole Grips.

Used a bit like an open-ended spanner, but these have more purchase.  They fit to ratchet handles or torque wrenches with a square drive.