These are web-sites that I frequent and enjoy and have found helpful.
Alpha and Omega Ministries, Dr. James White
Daily Dose of Greek (Professor Rob Plummer)
Daily Dose of Hebrew (Professor Mark Futato)
Beggar’s All Reformation and Apologetics (James Swan and his excellent research on Martin Luther and other Reformation issues. I also blog sometimes at this site.)
Cannon Fodder, Michael J. Kruger (Issues on the Canon of Scripture, early church history)
Dr. Kruger’s course on the Canon of Scripture.
Al Mohler (President of Southern Baptist Seminary)
John Piper, Desiring God
R. C. Sproul, Ligonier Ministries
Triablogue (Steve Hays, John Bugay, Jason Engwer, others)
Effectual Grace by Pastor John Samson
John McArthur, Grace to You
William Webster, Christian Truth (focused on analyzing Roman Catholicism)
Early Church Fathers
Baptismal Regeneration in the Early Church, by Timothy Kauffman
https://onefold.wordpress.com/ (Brian Culliton’s blog on Roman Catholicism and the Early Church evidence)
Early and Medieval Church History, by Dr. Ryan Reeves
Reformation and Modern Church History, by Dr. Ryan Reeves
Answering Muslims (David Wood)
Biblical Missiology (Georges Houssney)
Islam and Christianity by Abu Daoud
Apologetic and Answers to Difficulties and Questions book by book, verse by verse through the Bible.
Professor James Anderson – Proginosko
Green Baggins – PCA Pastor Lane Keister and other Presbyterians discuss theological issues.
Brandon Addison on Roman Catholicism
Together for the Gospel
Andy Naselli – Thoughts on Theology
I disagree with David Waltz on a lot of things, but he has a lot of great information on historical theology, church history, and the early church fathers.
David Waltz’ Articuli Fidei