Here's a list of some Christian tags. Those with an asterisk haven't been used to this point as far as I know. And general ones like "love" and "hope" will most likely be non-Christian posts.
General
Christian-trail Christianity
Christian Religion
God Jesus Jesus Christ* Lord Jesus*
Jesus is Lord* Jesus is risen* The Holy Spirit
The Bible Scriptures Word of God New Testament* Old Testament*
Bible Study Interpretation
John 3:16* The Ten Commandments Psalms Proverbs
Truth Prophets Prophecy Inspiration
Praise* Praise the Lord* Praise God* Hallelujah
Prayer Prayer-request The Lord's Prayer Our Father
Faith
Love Christian love* Agape
Peace Hope
The Gospel Salvation Grace Sovereign grace
The Cross Resurrection*
The Rapture Revelation Heaven Miracles* Angels
Church Fellowship* Baptism The Lord's Supper* Holy Communion* Testimonies* Pastors Sermons Sunday school Sunday
Missions* Missionaries*
Martyrs* Persecution*
Theology Apologetics* Morality Worldliness
Creation Genesis Good Good and evil Evil Sin
The Harbinger Apostasy* Hell Satan Lucifer
Denominations*
Evangelical* Baptist* Pentecostal* Charismatic
Protestant* Catholic
Calvinism* Megachurches
Christian music* Hymns*
Worship music CCM
Christian news*
Christian literature* Christian books* Christians movies* Christians memes
Pro-life Intelligent design*
Christian schools*
Homeschool Homeschooling
Also:
A Short and Simple Guide to Steemit - Outlines the main points and includes many helpful Steemit links.