Classic Sermon Index provides indexing to 64,000+ classic sermons. All are indexed and searchable by primary biblical reference, 75% are hyperlinked to the full sermon, 20,000 are indexed by topic. Date searching goes back to the 2nd century. 
Logeion aims to provide access to Greek and Latin resources for everyone everywhere. Logeion provides simultaneous lookup of entries in the numerous reference works that make up the Perseus Classical collection and many others. 
JSTOR’s open content program continues to grow rapidly—expanding access to journals, books, primary sources, images, and research reports. 
The Jesuit Online Bibliography is a free, collaborative, multilingual, and fully searchable database of bibliographic records for scholarship in Jesuit Studies produced in the 21st century. 
Research in Ministry® (RIM®) is a thesis and dissertation abstract database where users can search for and share the outcomes of research conducted in programs of study related to ministry, theology and religion. 
Database of Religious History is designed to serve as a centralized clearinghouse for scholarly knowledge of the historical record, bringing together a core of quantified, standardized data with qualitative comments, references to crucial resources, and links to on-line text and image databases.
Oxford Academic, Oxford University Press (OUP)’s platform for research, offers a single point of entry for access to scholarly and academic books and journals. 
Credo Reference is a full-text reference service. The Phillips religion collection includes The Brill Dictionary of Religion, The Routledge Companion to the Christian Church, Encyclopedia of Protestantism, and The Blackwell Companion to Jesus.
The Chicago Manual of Style Online is a guide to grammar, style, and usage for writers, editors, proofreaders, indexers, copywriters, designers, and publishers. 
Search the Atla and EBSCO databases for articles on your research topic. 