18 May – Saint Theodotus of Ancyra

Modern Hagiography

Roman Martyrology

Sanctorale Catholicum

Lives of the Saints by Alban Butler.

Lives of the Saints by Sabine Baring-Gould.

Our Birthday Bouquet Culled from the Shrines of the Saints and the Gardens of the Poets by Eleanor C. Donnelly.

Pictorial Half Hours with the Saints by Auguste François Lecanu.

Miniature Lives of the Saints for Every Day in the Year

Victories of the Martyrs by Saint Alphonsus Liguori.

Light from the Lowly volume II by Francis Butina.

Tradition in Action

Medieval Hagiography

Acta Sanctorum

Art & Architecture

Index of Medieval Art

Saints and their Attributes

18 May – Saint Felix of Cantalice

Saint Felix of Cantalice by Circle of Rubens (widely published as Saint Felix, but cannot be traced to its current location, apparently sold at auction in 2019)
Annus Dierum Sanctorum
Altissima paupertas eorum.
Their very deep poverty.
2 Corinthians 8.2
Gratias ago Deo.
I give thanks to God.
2 Timothy 1.3
Ego autem mendicus sum et pauper.
But I am a beggar and poor.
  Psalms 39.18
Dominus sollicitus est mei.
The Lord is careful for me.
Psalm 39.18

Modern Hagiography

Roman Martyrology

Lives of the Saints by Alban Butler.

Lives of the Saints by Sabine Baring-Gould.

La vie des saints 

Miniature Lives of the Saints for Every Day in the Year

Stories of the Saints Fifth Series by Mary Seymour.

Legends of the Blessed Sacrament Gathered from the History of the Church and the Lives of the Saints by Emily Mary Shapcote.

Legends of the Blessed Virgin by Jacques-Albin-Simon Collin de Plancy.

Tradition in Action

Early Modern Hagiography

Acta Sanctorum

Art & Architecture

Catalogo generale dei beni culturali

BeWeB

POP : la plateforme ouverte du patrimoine

Europeana

Warburg Institute Iconographic Database

Google Arts & Culture

Blessed Felix of Cantalice Resurrecting a Dead Child by Guercino

17C The Vision of St Felix of Cantalice

Post-Biblical Saints Art Index
Saints and their Attributes

Legends of the Monastic Orders as Represented in the Fine Arts by Mrs. Jameson.

A Handbook of Christian Symbols and Stories of the Saints as Illustrated in Art by Clara Erskine Clement.

Lives and Legends of the English Bishops and Kings, Mediaeval Monks, and Other Later Saints by Mrs. Arthur Bell.

The Saints in Art with Their Attributes and Symbols, Alphabetically Arranged by Margaret E. Tabor.

Saints and their Symbols: A Companion in the Churches and Picture Galleries of Europe by E. A. Greene.

The Saints in Art by Joseph Maria von Radowitz.

Emblems of Saints by Which They Are Distinguished in Works of Art by F. C. Husenbeth.

Customs & Devotions

Meditations on the Life, the Teaching and the Passion of Jesus Christ for Every Day of the Ecclesiastical Year with an Appendix of Meditations for the Festivals of Various Saints by Augustin Maria Ilg.

18 May – Saint Dioscurus

Modern Hagiography

Roman Martyrology

Medieval Hagiography

BHL Supplement

Acta Sanctorum

The Cult of Saints in Late Antiquity Database

Art & Architecture

Saints and their Attributes
Saints and their Emblems

The Saints in Art by Joseph Maria von Radowitz.

Emblems of Saints by Which They Are Distinguished in Works of Art by F. C. Husenbeth.