The following works will compliment any heraldic library.
Armorials and Ordinaries
The Dictionary of British Arms (4 vols.)
Papworth's An Alphabetical Dictionary of Coats-of-Arms
Burke's General Armory (1884) and Peerage
General Armory Two by Cecil R. Humphery-Smith
Paul's An Ordinary of Scottish Arms
Rietstap's Armorial General
Rolland's Illustrations (6 vols. in 3) and Supplements (9 vols.)
Siebmacher's Wappenbuch
Fox-Davies' Armorial Families (2 vols.)
Atienza's Diccionario Nobiliario
Gonzalez-Doria's Diccionario Heraldico y Nobiliario
Armorial du Canada Francais (2 vols. in 1) by Massicotte and Roy
Crozier's General Armory and Virginia Heraldica
Bolton's American Armory
Mayer's Saracenic Heraldry
Visitations
Visitation of Ireland (6 vols. in 1) by Howard and Crisp
Dictionaries
A Glossary of Terms Used in Heraldry by James Parker
An Heraldic Alphabet by J.P. Brooks-Little
A Dictionary of Heraldry by Charles Norton Elvin
An Encyclopaedic Dictionary of Heraldry by Julian Franklyn and John Tanner
General
Fox-Davies' A Complete Guide to Heraldry
Fairbairn's Book of Crests
Fox-Davies' The Art of Heraldry
Neubecker's Heraldry: Sources, Symbols & Meaning
Heraldry by F. Edward Hulme
Heraldry for Designers and Craftspeople by W.H. St. John Hope