Boost is the most important C++ utilities library.
It has very widespread use, and some of its features have been included or are candidates for inclusion on newer versions of the stdlib.
Full list of libs: http://www.boost.org/doc/libs/
Some of Boost libraries may be in separate packages / shared objects than others.
The library naming convention is: -lboost_XXX, e.g. -lboost_graph. Whenever you add a new Boost header don't forget to check if you linked to the required dependencies.