Below left is Trinity Chapel.  You can see a little bit more of the Johnson/Burgee building behind it.  At right is Trinity Rectory (1879-1880), at the intersection of Clarendon St. and fashionable Newbury St.  in the Back Bay  Note that originally the rectory was one story shorter.  In 1893 the roof was raised and a third floor added to accomodate the larger family of the new rector.
While Trinity Church certainly was the project that "made" Richardson as an architect, the style called Richardsonian Romanesque doesn't end with Trinity.
At left, is the New York State Capitol, a project Richardson became involved with after construction of the building was begun.  The style began as Renaissance, then incorporated Romanesque aspects.  Below left is detail from a grand staircase by Richardson.  Below is his Senate Chamber.
Richardson designed Albany City Hall (1880-1883, below left) and the Sard House (1882-1885, below right), also in Albany.  The unusual design of the the recessed porch with its bulging front caused it to be known as "Sard's bathtub."  The house now contains condos, connected to the tall building behind it.
Below: closeup of detail in City Hall doorway.