A few quick ideas.
The character has extensive experience as a factory worker, in commercial fishing, construction, taxi driver, postal worker, and other jobs not considered a desk job. When dealing with a situation that falls into a skill or knowledge involved with their job experience they may have a bonus on die rolls. Factory workers may know how to drive forklifts and metal working machines, taxi drivers may know how to handle traffic and find locations around town, etc.
Similar to the Law background but involving the underworld and seedy side of life. The character may be a reformed criminal, a bounty hunter, or perhaps even still doing some shady things on the side.
Alternate Skill System
Another alternate to the existing skill system is the also used method of using the Luck roll as a skill roll with the attribute bonus added to the roll. This works well as a simple skill check, the skill improves with each level, and one does not have to worry about assigning a difficulty number. Of course a bonus or penalty can be added to the roll as desired.