The Apostles Creed http://www.reformed.org/documents/wcf_with_proofs/
The Nicene Creed http://www.reformed.org/documents/wcf_with_proofs/
The Athanasian Creed http://www.reformed.org/documents/wcf_with_proofs/
The Westminster Confession of Faith http://www.reformed.org/documents/wcf_with_proofs/
The 1689 London Baptist Confession http://www.the1689confession.com/
Chicago Statement on Biblical Inerrancy http://www.bible-researcher.com/chicago1.html
Nashville Statement (on biblical sexuality) https://cbmw.org/nashville-statement/
The Gospel Coalition https://www.desiringgod.org/
Ligonier Ministries https://www.ligonier.org/
Radical http://radical.net/
Blogs
Challies https://www.challies.com/
Additional blogs can also be found at
The Gospel Coalition site at https://www.thegospelcoalition.org/
Books
Introduction to Systematic Theology by Wayne Grudem
Desiring God by John Piper
Let the Nations Be Glad by John Piper