Italian Renaissance Art - including Venice  

Oxford Art Online - Oxford's combined art databases, Dictionary of Art and Encyclopedia of Esthetics, searchable uniformly or individually.  Scholarly entries signed by authorities in the Renaissance area. 

Encyclopedia of World Art - hardcopy only.  Lilly, Perkins and Divinity Reference N31 .E4833 1959
- older, but longer essays on art topics and issue  + half of every volume is plates, may in color; - older

Pelican History of Art (series) Lilly Reference [various titles depending on period] Lilly N5300.P38
- the standard English-language history of art.  Continuously updated.  + extra images; good beginning bibliography
- Renaissance volumes include

Heydenreich, Ludwig Heinrich.   Architecture in Italy, 1400-1600. Architecture in Italy, 1400-1500. revised by Paul Davies. 
New Haven : Yale University Press, 1996.  Lilly Reference and Stacks N5300 .P455 v.38

Lotz, Wolfgang.  Architecture in Italy, 1500-1600. introduction by Deborah Howard.  New Haven : Yale University Press, 1995.  Lilly Refernece and stacks N5300 .P455 v.38, pt.2

Freedberg, S. J.  Painting in Italy, 1500-1600.  3rd ed.  New Haven : Yale University Press, 1993.   Lilly Reference and stacks N5300 .P455 v.35, 3rd ed.

Digital Librarian - Medieval and Renaissance Studies [webportal] - the Renaissance component of a variety of better (free) websources.

Symbol Dictionaries

Hall, James.  Dictionary of subjects and symbols in art.  Edition  2nd ed.   Boulder : Westview Press, c2008.  Lilly Ready Reference N7560 .H34 2008

Saints

Oxford Dictionary of Saints [online]

Kaftal, George. Iconography of the saints in the paintings of [region] Italy. Florence, Italy : Casa Editrice le Lettere, 1985.  Lilly Reference N8080 .K255 1985
 

Baring-Gould, Sabine. Lives of the saints. 16 vols.  Edinburgh, J. Grant, 1914. Lilly and Divinity Reference BX4655 .B3 1914.

Artists Biographical Dictionaries

Dictionary of artists - "Benezit".  Paris : Gründ, 2006.  14 vols. Lilly Reference N40 .D5213 2006

Allgemeines Künstlerlexikon : die bildenden Künstler aller Zeiten und Völker. Munich/Leipzig : K.G. Saur, 1992- 70 [projected] volumes.  Lilly Reference  N40 .A63 1992   

Period Dictionaries

Zirpolo, Lilian H.  Historical dictionary of Renaissance art.  Lanham, Md. : Scarecrow Press, 2008.  Lilly Reference N6370 .Z57 2008 
  

Encyclopedia of Italian Renaissance & Mannerist art.   New York : Grove’s Dictionaries, 2000.   Lilly Reference N6370 .E53 2000

Decorative Arts

Grove Encyclopedia of the Decorative Arts - a decorative arts dictionary strong on Renaissance terms and objects

Architecture

Campbell, Gordon.  Renaissance art and architecture / Gordon Campbell.  Oxford ; New York : Oxford University Press, 2004.   Lilly N6370 .C32 2004   - a dictionary of places, terms and literary sources.

Murray, Peter. Architecture of the Renaissance.  New York, H. N. Abrams 1972.  Lilly A510 .M87 1972 - part of the History of world architecture series, includes cut-aways of buildings and spectacular plates.

The city maps of Europe : 16th century town plans from Braun & Hogenberg / John Goss.  Published  Chicago : Rand McNally, 1992.  Perkins/Bostock Oversize 912.4 B825, C581, 1992 In process-LC  
 

Renaissance art reconsidered : an anthology of primary sources / edited by Carol M. Richardson, Kim W. Woods and Michael W. Franklin.   Malden, MA ; Oxford : Blackwell Pub. ; Milton Keynes, UK : In association with The Open University, 2007.

 
Seymour, Charles.  Michelangelo, the Sistine Chapel ceiling: illustrations, introductory essays, backgrounds and sources, critical essays.    New York, Norton [1972] 

Census of Antique Works of Art Known in the Renaissance - Wilhelm Humbolt University.  Online index of classical-era works extant during the 15th-16th centuries, culled from Renaissance writings such as books, letters and guides.  Many are untraced (i.e., unknown what they are today).  In every case, the original citation to the work mentioning the object is sited.

Duke RBMSCL (Rare Book, Manuscrpt, and Special Collections Library) has a vast array of facsmile books, rare-book printed material and manuscripts from the Renaissance era.  Since many titles are not extensively cataloged, it's best to consult RBMSCL reference librarians directly on what might be there in a certain area.