Life of Don Bosco, Founder of the Salesian Society, 2nd edition, by J.M. Villefranche, translated by Lady Martin (London: Burns & Oates, Limited; New York: Catholic Publication Society). May be read online and available in pdf format at Google Books.
Patrology: The Lives and Works of the Fathers of the Church, by Professor Otto Bardenhewer, D.D., Ph.D., translated from the 2nd edition by Professor Thomas Joseph Shahan, D.D. (Freiburg im Breisgau; St. Louis, Mo.; Karlsruhe; Munich; Strassburg; Vienna: B. Herder, 1908). With Imprimatur, and with the approbation and recommendation of various archbishops and bishops. May be read online, and available in pdf, mobi, epub and other formats, at Open Library and Internet Archive, with a 2nd copy at Internet Archive, a 3rd copy at Internet Archive, and a 4th copy at Internet Archive.
St. Polycarp, Bishop of Smyrna, by Blomfield Jackson (London, Brighton: Society for Promoting Christian Knowledge; New York: E. & J. B. Young, 1898). May be read online, and is available in pdf, mobi, epub, and other formats at Internet Archive with a 2nd copy at Internet Archive. [This work does not appear to have been written by a Catholic Christian, but it provides the life and works of a great early Catholic of the one true Church.]
Miniature Lives of the Saints for Every Day in the Year, 21st edition, edited by Henry Sebastian Bowden of the Oratory (London, Burns & Oates; New York, Cincinnati, Chicago: Benziger Brothers). In 2 Volumes.
Volume II (July-December) of the 2nd edition (London, Burns and Oates, 1877) may be read online, and is available in pdf, epub, mobi and other formats, at Internet Archive.
Life of St. Vincent de Paul, by Frances Alice Forbes (London: R. & T. Washbourne, Limited, 1919). With Imprimatur. Part of the series Standard-bearers of the Faith: A Series of Lives of the Saints for Young and Old.
Catholic Church: Where Are You Heading? Theologian Dániel Fülep’s interview with Bishop Athanasius Schneider Auxiliary Bishop of the Archdiocese of Saint Mary in Astana Astana, Kazakhstan, July 2018, translated by Gábor Sallai, edited and published by Dániel Fülep (Budapest, 2018). Available in pdf format at the Magyar Elektronikus Konyvtar. This text states: “The texts can be freely copied, distributed or otherwise used, subject to proper acknowledgement of the source.”
Homilies on the Resurrection of Our Lord Jesus Christ and the Post-Resurrection Narratives, by Saint Augustine {from Homilies on the Gospel according to St. John and His First Epistle, by St. Augustine, Bishop of Hippo, in Two Volumes, Volume II (Oxford: John Henry Parker; London: F. & J. Rivington, 1849), which larger work is available on pdf, epub, mobi and other formats at Internet Archive}:
The Japanese Martyrs; or, a Brief Sketch of the Lives and Martyrdom of the Franciscan Saints, Who were Canonized at St. Peter’s, in Rome, by Pope Pius IX, on Whit-Sunday, June 8th, 1862, by the Rev. Father Emmanuel Kenners, O.S.F. (Manchester: Alex. Ireland & Co., 1862). May be read online, and available in pdf, epub, mobi/kindle and other formats, at Internet Archive.
A Sketch of the Life and Works of the Venerable Don Bosco, Apostle of Youth, Founder of the Society of St. Francis of Sales, by M. S. Pine (Philadelphia, Pa.: Salesian Press, 1916). With Imprimatur.
Manual of Patrology, 3rd edition, by the Very Rev. Bernard Schmid, OSB, with the approbation of the Bishop of Freiburg, freely translated from the 5th German edition by a Benedictine, revised with notes and additions for English readers by Msgr. V.J. [Victor Januarius] Schobel, with Preface by the Right Rev. Bishop J.C. Hedley of Newport (St. Louis, Freiburg, London: B. Herder, 1911). With Imprimatur. May be read online, and available in pdf, mobi/kindle, epub, and other formats at Internet Archive. An earlier edition (St. Louis, Mo.: B. Herder, 1899) is available at Open Library and Internet Archive (linked by the Free Traditional Catholic Books page of Traditional Catholic), with a 2nd copy at Internet Archive (front pages missing) and a 3rd copy at Internet Archive.
[Note: What distinguishes this book from the likewise erudite works of Dr. Otto Bardenhewer and Dr. Joseph Tixeront is the fact that its historical overview of the Fathers is preceded by a general introduction to the field of patrology, as well as a detailed “Introductory and Propadeutical Part” discussing the methodology of patristics: the authority of the Fathers and the way their works are examined, used, and understood.]
“[The Gospel’s] saving truth and rules of conduct… are contained in the written books and in the unwritten traditions… received by the Apostles… dictated either orally by Christ or by the Holy Ghost, and preserved in the Catholic Church in unbroken succession… [N]o one… shall, in matters of faith and morals pertaining to the edification of Christian doctrine, distorting the Holy Scriptures in accordance with his own conceptions, presume to interpret them… contrary to the unanimous teaching of the Fathers.” (Council of Trent, Session IV)
“Christ the Lord in whom the full revelation of the supreme God is brought to completion (…), commissioned the Apostles to preach to all men… [T]he Apostles left bishops as their successors, “handing over” to them “the authority to teach in their own place.”… And so the apostolic preaching… expressed in a special way in the inspired books, was to be preserved by an unending succession of preachers until the end of time… The words of the holy fathers witness to the presence of this living tradition…” (Second Vatican Council, Constitution on Divine Revelation)