Click photos to enlarge.
Notes in italics from Hampshire and the Isle of Wight by Nikolaus Pevsner and David Lloyd (1967)
Yale University Press, New Haven and London. Other information is from Hampshire Treasures. 

In Little Minster Street, 17th century. Painted brick walls and brick string course. Old tile roof with two dormers. Contemporary window frames and mullions above. C.19 sash windows and door below.
In Great Minster Street. Minster House, early C18. Five bays, chequer brick, hipped roof. Later doorway with Tuscan columns and broken pediment. The house faces the front of the cathedral.
In The Square. ... facade towards the cathedral. Five bays, three storeys, grey headers and red dressings. Doorway with unfluted Ionic columns and a pediment. Fluted frieze.

In St Peter's Street. Avebury House is dated 1690 by the MHLG (Ministry of Housing and Local Government). Five bays, chequer brick. Very elegant late C18 doorcase with Tuscan columns and a fluted frieze. 

In St Peter Street. Milner Hall, 1792. Gothic revival style. Large rectangular hall of red brick, flint panels to rear. Cement-rendered front to St. Peter Street, with shelved buttresses, originally crowned by pinnacles over crenellated parapet. String course ornamented with rosettes and symbols of St. Peter. Drip moulds on head stops over pointed windows. Later gabled porch. North wall with quatrefoil window. Architect. J. Carter.
In Jewry Street. Presbytery, Georgian, six bays and a parapet. Doorway with broken pediment on Corinthian pilaster.

LIBRARY, Jewry Street. Built as the Corn Exchange in 1836-8. By O.B. Carter, evidently a man of considerable talent and character. Yellow brick and white ashlar. Classical but with pronounced Italianate roofs, i.e. low pitches and deep eaves. Even the square turret in the middle has one. The turret is placed behind the central portico, inspired by Inigo Jones's St Paul, Covent Garden, with its Tuscan columns and its Etruscanly deep eaves to the pediment. Three-bay links with arched windows to end pavilions. ...

In St Swithun Street, pair of houses of C18. Refronting of older buildings. C.16/17 work at back visible from College Street. 3 storeys. Colour washed brick with parapet and old tile roof. Part tile hung at rear. Pair of doors in centre with contemporary steps, plain surrounds and moulded cornice. Band at first floor level. First floor Venetian window at rear in College Street. Also Rear Garden Wall. C.18. Part renewed. Twelve rusticated red brick piers with ball finials. Dwarf brick wall with stone coping between.
Also behind this wall, the rear of Cheyne Court in the The Close.

On the opposite side of College Street (south side). Nos. 13-18 must be C16 in their bones - see the overhang. No.15 has a pretty C18 oriel. ... 
2nd picture: The house in which Jane Austen died in 1817. 18th century.
3rd: No.7 (on the N side) seems C18 (five bays, two storeys) but has to the S one window with a decorated brick surround which must be late C17. The College follows. 

In Colebrook Street. Circa 1800. 2 storeys and attic. Brick walls, stone moulded cornice and stone capping to parapet. Old tile mansard roof, with two dormers. Tile-hung side wall. Semi-circular arch over doorway with tympanum and fanlight. Recessed door with free standing Roman-Doric columns and entablature. Ground floor windows with similar arches and fan tympana.
In Market Street, former Market House, side and rear (shop front on the High Street). ... much interfered with ... It was built in 1857 and has (still) Greek Doric columns and wreaths in the frieze.

Also in Market Street, Morley College, founded in 1672 as the College of Matrons, but now of 1880 (by Colson). The character of roof and facade was kept, though the details are characteristically 1880.