Up until today, I had never come across this "church" before: Marcionite Christian Church.  Was introduced to it by a Gabber, who claims to be a Quaker but attends a Marcionte "church," who was insulted by being referred to as a heretic.

They claim to be "the pre-Nicean Church" which, according to their website, is being "rebuilt."

They also claim to be "the first Christians" and obviously adhere to the heresy of sola scriptura (which to me seems a bit odd as that really wasn't a thing until Luther?).

From their website:

The Marcionite Christian Church was once the largest Christian church in existence, spanning the known world with millions of believers. It was founded in 144 A.D. and is responsible for the creation of the first Christian bible of that same year.

That bible consists of The Gospel of the Lord as revealed to Paul the Apostle and the original Epistles of Paul (one Gospel, ten books) and remains unchanged to this day. The Very First Bible is the foundational Christian canon to which virtually every denomination can trace its roots.

Sola Scriptura

The Marcionites are not gnostics, there is no 'secret knowledge' involved in our faith. Our beliefs (Sola Scriptura) are on full, unapologetic display in The Very First Bible of 144 A.D. and they predate any other existing church.

Despite the vast size and reach of the church at one time it was never a top-heavy institution weighed down with multiple levels of hierarchy, management and gatekeepers. You are a child of God, sovereign and connected to Him right now. The role of the church is to nurture and support that understanding and relationship while providing an avenue for brotherhood and fellowship.

Through the prism of current events it is with great sadness we watch as mainstream 'Christian' churches, subverted and judaized by corruptive influences, crumble to the touch like termite-infested wood as a new wave of evil sweeps across the world behind the mask of a fake plague.

Like the persecuted first Christians before us, we hear the cries of distress and open our doors to the abandoned flock. Our creed is simple: One Gospel. One Bible. One Faith.

Not only are the Marcionites credited with the first Christian bible, their church bears the oldest inscription of Jesus' name in the world. It was dated 318 A.D. and discovered by French archaeologists in 1870, carved into the doorway of a Marcionite church in Syria (video). Learn more about the Marcionite Christian Church, The Very First Bible and our doctrinal canon - we hope you'll join us.

"But I certify you, brethren, that the gospel which was preached of me is not after man. For I neither received it of man, but by the revelation of Jesus Christ." (Galatians 1:8-9)

"I marvel that ye are so quickly changed, from him that called you in the grace unto a different gospel: Which is not another; but there be some that trouble you, and would pervert the gospel of Christ." (Galatians 1:4-5)

God was revealed only through Jesus, not through an alien religion

The Marcionites determined that the Hebrew bible (Old Testament), and the deity portrayed within it, are diametrically opposed to the teachings and salvation of Jesus Christ. The proof is self-evident in the form of the scriptures themselves and that's why it wasn't included in The Very First Bible.

And this from their F.A.Q. page:

As for the heresy charge, the Roman Catholic Church didn't exist until hundreds of years after the Marcionites formed theirs. [[B.N.  ]] Also, many writers, like Tertullian, were hired to smear the Marcionites but what does St. Joseph tell us about Tertullian? "As to Tertullian, I have nothing else to say except that he was not a man of the church." We agree with our Catholic brothers on this point fully.

They seem to be based out of Greece.  What an odd bunch.