Taking a slightly different tack from "renaissance man", which focuses on broad learning and education; a high-brow appellation, there is the category of a "generally useful" individual.
This is a "gets done whatever needs to get done" sort of characteristic: the human analog to a Swiss Army knife. For that, you have a couple of options:
- a person whose job involves doing many different types of work
- a person having many diverse activities or responsibilities
a person who does all sorts of jobs; general assistant
and the more down-to-Earth:
Guy Friday / Gal Friday:
a person who acts as a general assistant in a business office or to an executive and has a wide variety of especially secretarial and clerical duties.
and finally the political and slightly intimidating:
A body man is, in U.S. political jargon, a personal assistant to a politician or political candidate. A body man accompanies the politician or candidate virtually everywhere, often arranging lodging, transportation or meals, and providing companionship comprising providing snacks, a cell phone, and any other necessary assistance.