Among other things, I want to help people avoid certain bad Comparative Mythology research that comes from both Believers and Skeptics. That has it's origins in the bad research of 18th and 19th century Thesophists and Alexander Hislop.
Before recommending again what I've said on the subject, I want to recommend some material by people more formally qualified then I am.
One is the Inspiring Philosophy YouTube channel. I don't agree with them on everything but they have some good material on this subject. One is a video called Is The Trinity Pagan? They have a series on Was Jesus a copycat Savior? And I like their video Easter is not Pagan. Their equivalent videos on Christmas also have good information but there they say stuff I can't endorse, they do tolerate more Catholic reclaiming of Paganism then I'm wiling to.
[Update August 2018: I need to add a major qualifier to my endorsement of Inspiring Philosophy's Copycat Savior playlist since in the new Inanna video he engages in the massive Hersey of denying The Harrowing of Hell.]
Another good YouTube channel is Religion for Breakfast, they come at things from a secular perspective, so as such certainly say things I don't agree with here and there. But sometimes that outsider perspective is useful. He has a video on the Cult of Mithras Explained, and his own about Why is Christmas on December 25th?
Chris White did a lot of stuff on this. In a way he's still more a conspiracy theorist then I am now. And to some extend I recently don't find his work as re-watchable as I used to. Still I have my own Playlist of Chris White videos on YouTube. Not everything there is about Comparative mythology, the ones about Zeitgeist and specific New Agers are the key ones.
Now for some of my own work.
My most important post on this topic is Paganism is about what you Believe not what you do from Sola Scirptura Christian Liberty on BlogSpot.
On m A Chronological View of Revelation blog. I actually think I do deal with the Letter of Hadrian from the Histora Augusta better then IP did in their Serapis video. And I also talk about Christmas Hanukkah, and December 25th.
And on my now semi-defunct Revised Chronology views of Mithrandir blog I talked about a lot of the Nimrod disinformation.
So the first two YouTubers I mentioned are the best starting point. I'll see how many videos I can successfully embed here. On some of these I've left comments in the comments sections.
https://www.youtube.com/playlist?list=PLTZaOylOgJT-GLyroghQSfXAUPAusaEI4
Though he still says things I disagree with like considering Paul's Epistles older then any of the Gospels.